Thank you very much, Stacey. Well, good afternoon, ladies and gentlemen. I'd like to welcome you all to my webinar.
Our webinar this afternoon is going to be very much one of two halves. The first half is going to be focused on the impact of management on bird health, and then we'll move on to a guide as to how to postmortem a backyard chicken. I think it's very important to stress that despite avian influenza having been picked up in Dorset and in Warwickshire in the last few weeks, there's very little in the way of true disease in the UK, and the majority of conditions we see in backyard flocks tend to be driven by management and husbandry rather than by pathogens as a primary cause.
So we'll jump straight in and talk about one of the first conditions that you'll find to deal with in backyard flocks, and that is broodiness in backyard chickens. In the wild, a chicken would typically lay a clutch of 15 to 20 eggs in a dark, secluded area. When she'd finished laying her clutch, she would become broody.
During the broody period, the hen will sit on her eggs 24/7, and she'll only leave the nest for about 5 minutes each day to eat, drink, and defecate. During the incubation period, the hen will turn the eggs regularly to ensure that the eggs are evenly warmed and to stop the embryo sticking to one side of the shell. Normally, after 21 days, the chicks will hatch out and the broody hen will move off the nest with a brood of chicks, taking them to food and water.
Now, it's a sad fact that the majority of backyard flocks do not contain a cockerel, and therefore all of the eggs laid in them flocks are infertile. Now the problem is that the broody hen doesn't know this. So if nothing hatches out after 21 days, the hen will keep going and can remain broody for up to 6 to 8 weeks.
There's 4 different problems with this. First and foremost, during the broody phase, the chicken's appetite is diminished, and she will lose body weight. So if she's evolutionarily designed to not eat very much food for 3 weeks, if she goes to 6 or 8 weeks as being broody, she's going to lose a heck of a lot of condition.
During the broody phase, chickens tend not to dust bathe, and that means that parasites such as red mites and lice can build up in their plumage. And if you can imagine if you combine a heavy red mite burden with the chicken that's not eating much, it can lead to disaster. Brody hens can be very aggressive, and what we tend to find is that you can see in the photograph on the bottom right, a broody hen, when approached, will puff up her feathers to make herself look big.
She'll growl at you, and when you go to move her off the nest, she'll peck you. So they're an inconvenience to both owners and to other chickens within the flock. So they end up having to lay their eggs elsewhere because the broody hen's hogging the nest itself.
So if you Google how to break broodiness in backyard chickens, there's a plethora of old wives' tales out there on the internet, the most cruel being to dip the chicken in a bucket of cold water. I have to admit I don't advocate this at all. The recommended procedure is to have a wire button cage in a cold bright area and to pop the chicken in that for a week with food and water because chickens like dark, warm, secluded environments to go broody.
So if you put them in a bright, cool area, then that tends to break the broodiness. You can inject the chickens with romacryptine to interfere with prolactin levels, but I think that this is unnecessary. It's really important from a management perspective that eggs are collected regularly.
If you constantly remove the eggs from the nest, there's a less likely chance that the chicken will become broody. Genetics plays a huge role in broodiness. We tend to find that modern commercial laying hens have had broodiness spread out of them since the 60s, and it would be very rare for a commercial brown laying hen to become broody.
If owners want chickens that are going to become broody, I would advise that they go for either a bantam or a silky cross, as these breeds make excellent broody hens. The next most frustrating thing that we see in backyard practise with backyard chickens is feather loss, and I'm going to cover a number of rather odd categories of them. We'll talk about moulting, birds being pecked by their flockmates, self pecking, what I've deemed to be the bald bum, which is slightly odd, cockerel damage, and I'm not going to talk about red mite today because that's a webinar in its own right.
But certainly if anyone's interested in more information on webinar or Redmite, there's a webinar that I've done with the webinar vet team on it and also there's some information in your guidance notes. So with moulting, typically in the autumn time, chickens over about 2 weeks to 8 weeks, will replace all of their feathers gradually. During this time, the bird can look moth-eaten, and owners tend to get very concerned.
It's really important to remember that a chicken's feathers are typically 85% protein, so some owners want to supplement the bird's diet during the moult with synthetic amino acids, and these can be bought from many local agricultural merchants and can be administered in the drinking water. But personally, I don't think it's necessary, provided the bird's been fed a balanced diet. It's very rare for chickens to moult outwith the autumn period, although if a chicken has been broody, you'll often find that she will go and moult afterwards.
And it's really important to remember that chickens moult their scales and their legs at the same time as they moult their feathers. So just remember that when you're treating any chickens with scaly leg. One of the most common causes of feather loss other than moulting is pecking by other birds.
Now, whenever we think of feather pecking, we tend to think of aggressive pecking, whereby the more dominant birds in the flock are pecking their subordinates. But this isn't the case. Feather pecking by other birds tends to be.
Much less aggressive and it's more of a vice that you get in chickens, so you tend to find that they actually suck or gently pull the feathers, and the bird that's being pecked tends not to withdraw. They tend not to mind too much. And really what this is is it's a stereotypical behaviour and we believe that it's driven either by boredom or nutritional deficiency or due to the birds not having a place to dust bathe.
So whenever I'm presented with a backyard flock whereby we've got feather pecking, I think it's first and foremost to look at the nutritional side of things. Backyard chickens only need the nutrition supplied by a mash or pellet. They don't need treats, corn, or the like.
If owners do wish to give their chickens treats, some mealy worms are OK or a very small amount of mixed corn in the afternoons. But it's really important to stress, like other species, obesity is really common in chickens. I think in terms of boredom, if you want to alleviate it, there's some really good peck blocks that owners can buy out there, or they can hang up a piece of broccoli or some cabbage, the chickens to start pecking at.
It's really important that chickens have adequate space to dust bathe, and one of the best things I've seen for backyard chickens is to use a cat litter tray and to put some kids' places and in it mixed with some mic powder, and that makes an excellent dust bathing substrate. Lack of space can sometimes be an issue for backyard flocks, but it tends to be people that are breeding them that have lack of space because they hatch out too many chicks, rather than people rehoming a couple of ex-pattery hens. And really important to stress, feather pecking is rarely due to bullying.
That is really, really rare. Self-pecking in chickens is incredibly rare and is caused by the depluming mite known as Nemitocotesalilee. This mite burrows deep down into the feather shafts and causes pain and irritation, and the bird will go and remove its own feathers.
There's only one treatment for the pluming mite in backyard flocks, and that is to use ivermectin spot on. Now this is an off-label treatment, and legally under the cascade we must apply a minimum of a 7 day egg withhold and a 1 or 28 day meat withdrawal period. However, as you'll see when we come onto the postmortem section of the webinar, typically a chicken's ovaries have got about 2 weeks' worth of eggs sitting there ready to be laid, and I would always recommend that when using the cascade, you always set a minimum of a 14 day egg withdrawal.
We tend to use the ivermectin 1% drops and apply them as a spot on to the back of the neck after parting the feathers. And typically we would use one drop of ivermectin 1% for every 500 grammes body weight. So bald bum, sometimes owners present laying chickens to us with what looks like baboon's backsides.
These chickens tend to have very bald, bright red bottoms. It's totally normal in flux with the cockerel for the hen to have a bald bottom because whenever the cockerel's mating with her, his tail and her tail will come into contact and they will rub the feathers off each other. Equally important that when chickens are laying a lot of eggs and sitting on the nest, they will eventually remove the feathers from around their vent.
And ultimately, this exposed skin tends to go a bright red colour, a bit like men whenever we're losing our hair. This photograph here is quite typical of what we would see in breeding flocks. You'll notice that on the top of the head there's a very minimal loss of feathers where the cockerel's grabbed onto the hen with his beak, and on her lower back she's missing feathers where his breast has been resting up against her during mating.
What's really quite strange is that cockerels with a flock of typically 8 to 10 hens will always prefer to mate with one chicken, and I'm not quite sure what makes an attractive hen, but we'll come on to talk a little bit more about this in a moment. One of the interesting ways of dealing with over mating in chickens is to go online and buy saddles for the birds, and you can get these fancy saddles for chickens in a range of designs, colours, shapes, and sizes, and they protect the hen from the cockerel. I must admit I'm not entirely convinced that they're that comfortable for the hen to wear, and I'd rather remove the cockerel for a few weeks to let the hens recover and have a bit of a break.
Normally when a cockerel has mated with his hens, they will remain fertile or their eggs will for up to 3 weeks. So hens can store the cockerel sperms for quite a considerable period of time. We're not going to go on to our first whole question.
OK, Richard, I've launched that first poll question for you. So the first question, what's the best way to break broodiness in a chicken? So since I've launched that whole question, a new window should have opened on your screen, and you can choose, from the options that Richard has put in the multiple choice question.
We can't see who votes for which options, so please don't be shy. We can just see the percentage of delegates who have chosen which options. So even if you're not sure, it's worth having a guess and checking your knowledge, and, I'm sure Richard will discuss the results when I finish the poll question, and I'll just give people perhaps a couple more seconds to vote.
OK, I'll end the whole question now. So, Richard, we've got an overwhelming majority, 90% of delegates saying option C, put in a bright area in a wire bottom cage. 10% of attendees have said put in a warm dark coupe, and 5%, said replace with eggs, the eggs with golf balls.
But the correct answer is C, to put the chicken in a bright area in a wire bottom cage, and thankfully, I don't believe anyone has answered B dunking the chicken in cold water because that's just downright cruel. OK, we'll move on to the next part of our webinar. So we're gonna talk a little bit now about the male of the species.
One of the reasons to have cockerels with a flock of chickens is of course to reproduce and hatch out chicks, but cockerels will also guard and look after their hens within their harim. The downside to cockerels is that they make an awful lot of noise and they're a great way of peeing off your neighbours. Now what you mightn't be aware of is that the deeds to most houses actually forbid the keeping of livestock, and from a legal perspective, chickens are livestock.
Normally, local authorities will turn a blind eye to this. However, whenever cockerels start upsetting the neighbours, that can soon rapidly change. Cockerels can be aggressive towards people and to indeed other cockerels within the flock, and you can see in the top photograph the spurs on one of my Appenzeller cockerels that we have, and you can see just how much potential there is for him to damage both the hens when he's mating with them and indeed people when you're going in to collect the eggs.
Additionally, some cockerels have got very big combs, and that can stop their heads getting into drinkers and feeders and can actually cause damage to their combs. And some people don't want their eggs to be fertile if incubated. So for example, if you've got a broody hen and you happen to forget to collect the eggs for a few days, you may have partial embryonic development within the egg when you go to have your fry in the morning, which isn't particularly pleasant.
Now, generally speaking, we tend to recommend if you're going to keep a cockerel that you've got 1 male for every 8 to 10 hens. The sad fact of life is that 50% of all the eggs that hatch are actually cockerels, and that means that 9 out of every 10 cockerreels tend to be unwanted, assuming every flock of chickens had a cockerel. So it's a massive problem for owners.
One option would be rehoming, but no one really wants to buy these cockerels or indeed to get them for free. Euthanasia, sadly is an option, whether that's just normal euthanasia or the bird ends up getting fattened and to be eaten. Hormonal implants work exceptionally well in hens, but not in roosters, and the reasons for that are that the physiology and hormonal balance within chickens is slightly different from mammals.
So for example, if you wanted to put a hormonal implant in a hen, it will stop relaying, but it doesn't work the same in a cockerel. We can castrate cockerels, but if you're going to do it, you must do it prior to puberty, so that will be before 4 months of age. Now the downside with chickens is that the testes of the cockerel are at the cranial pole of the kidneys, and you can see them in the right hand photograph, what looks like these very pale bean shaped structures.
And unfortunately this is a job for a GA, and I would tend to recommend that a specialist avian surgeon does it, so it's not a job for a general practitioner or a small animal vet. I would tend to refer them on. And that of course incurs a significant cost.
You can potentially keep cockerels in darkened coops in the morning to stop them from crowing. The problem is if you're going to stop all the light coming into the coop, the chances are you're going to stop airflow, and I don't think that's a particularly good idea for either the cockerel or the rest of the birds within the flock. So I think we've all got to accept that probably 9 out of every 10 cockerels do end up having to be euthanized within a flock.
We'll hand you back to Stacey for our 2nd pool question. OK, Richard, I've just launched that second poll question. So the second question is, what is the most common cause of baldness in hens?
And people are busy voting away now, so feather pulling by other birds, aggressive pecking by other birds, mating damage, red mites, or moulting. Just give people a bit more time to respond to that question, Richard. No problem.
OK, I'll stop that whole question now. And the results are 30% said feather pulling by other birds, 5% are say aggressive pecking by other birds. The biggest proportion of people, 45% said mating damage.
Nobody said red mite, and 25% said moulting. OK, well, my answer that I had was feather pooling by other birds, predominantly because in the summertime, you tend to find that you're not getting birds moulting. You can have a bit of mating damage, but peak mating time for chickens tends to be in the spring.
Red mites, although they can irritate chickens and cause some feather loss, are relatively rare in terms of a cause of loss of feathers. It tends to cause more of an anaemia. And aggressive pecking generally doesn't cause baldness.
The other thing to remember in the summertime is that hot weather precipitates stress, and that can sort of encourage chickens to engage in vices such as feather pulling. We're now going to move on to diarrhoea, so I hope everyone's had their lunch. So we've got a photograph here of 3 different chicken poos.
Now I hope that you'd all agree that the dropping on the left hand side of your screen is normal. You've got a firm faecal mass with a bright white urate cap. The central photo is of frothy yellow droppings, and this is abnormal, so I think hopefully you'd all agree that this is not a normal chicken poo.
The dropping on the right hand side is a deceptive one. It looks like Cadbury's caramel, both in terms of colour and consistency. This is a normal chicken's dropping.
So chickens have got a well developed blind gut known as the siki, and they've got a pair of these, and 1 to 3 times a day they will empty the siki and they will produce this caramel-like dropping, and owners very frequently mistake it as being diarrhoea. As in all species, just because a chicken's got diarrhoea doesn't mean it's massively serious, and it doesn't mean it needs veterinary treatment. So I think if you think of a group of 30 to 100 people, there might be one of us in the room with slightly dodgy droppings.
It doesn't mean we need to go and see our GP. I've got a rather peculiar looking set of differentials for diarrhoea in backyard chickens, because if you open up the textbooks, you can find 50 or 60 different pathogens that cause diarrhoea, and you can wrap yourself up in knots. So I've tried to think about it in a very basic way.
We've got coccidiosis in our differentials list, but generally speaking, coccidiosis is a disease of young birds up to about 4 months of age. And when you get coxy and backyard flocks, you tend to find they're either dying or you've got bloody droppings that look like raspberry jam. And I've got a photograph in our PM slides in a minute.
Bacterial infections of the gut tend to be the most common cause of diarrhoea, but there's lots of predisposing factors to bacterial enteritis which I want to touch on. Worms potentially can cause diarrhoea. We can have renal or hepatic issues, and it's really important to remember that chickens urinate and defecate in one go.
So sometimes if birds have got polyurea, it will appear as diarrhoea. And very rarely a chicken that's egg bound can have a vent discharge, which again owners mistake as diarrhoea. In the photograph on this slide, this is a chicken's backside to orientate you, and you can see that there's some faecal matter clinging to the feathers around the bird's vent.
This is known in the poultry trade as being vent pasting and is a good indication of poor intestinal health. So normally in my head when I've got a chicken with diarrhoea, provided that it's otherwise well, I'm thinking it's secondary to other factors. It could be worms, and I would recommend doing a faecal worm egg count, using the McMaster method.
We would typically say that a worm egg count of over 400 eggs per gramme would warrant deworming. If we find any hare worms, any capillaria, we would recommend worming irrespective of the worm egg count. The best option for worming backyard chickens is to use flubin vet, as it's got a zero egg withhold, and that is administered in the feed for 7 consecutive days.
Fluenvet can be purchased and then mixed at home, or even better, go to your local supplier and ask them to order you in some feed that's pre-medicated with Fluenvet. This tends to be cheaper and it's a heck of a lot easier. There's a whole plethora of viruses which can cause bacterial diarrhoea in chickens, but generally they tend to cause transient diarrhoea, and the bird gets over it.
You can send samples off for virus isolation, but by the time you've got the results, the bird's either died or recovered, and you tend to be landed with a massive bill from the veterinary Laboratories agency for several 100 pounds, which the owners are often reluctant to pay. I think it's worth looking for coccidiosis in younger birds, and again, you would do it through the faecal worm egg cunt. Stress can precipitate diarrhoea and backyard flocks, and very commonly a poor diet, and I come back to what I said earlier about making sure that birds are fed a balanced diet.
One of the things that's very unusual about chickens is that their egg size is heavily dependent on the levels of organic acids and amino acids within their feed. And if owners are giving their birds lots of treats or kitchen scraps, then this can frequently alter the egg size and lead to dystopia or egg binding. So a typical laying chicken that weighs 2 kilogrammes should be getting about 120 to 150 grammes of pallet or mash every day with maybe a tiny handful of corn and some mealy worms as a treat.
Certainly the feeding of kitchen scraps to backyard chickens is illegal unless the household is vegan. I've written in dirty water, and you might think that's a bit obvious, but it is amazing the number of owners who do not change their backyard chickens water on a daily basis. Chickens are messy.
They scratch around in the bedding, and they can scratch bedding into their drinkers. And additionally, in a lot of coups there's quite bright light, and you tend to get algal growth within the drinkers, which can upset the bird's gut. Very frustratingly, even if you do give the chicken nice clean water to drink, they'll find the nearest puddle when you let them out in the morning to go and drink from.
So it's really important to drain any puddles in the range. Potentially you can look at doing faecal culture with bacterial diarrhoea, but most of the time you only ever tend to recover E. Coli or Clostridia, and you're no further along in your diagnosis because these are commensal organisms.
I always ask myself, does the bird really need to be treated? And to be honest with you, most of them probably don't. If it's otherwise well and you've ruled out all the predisposing factors, then I would potentially tend to send the bird home on either probiotics, electrolytes, or apple cider vinegar.
And the concept behind apple cider vinegar is that it acidifies the pH of the gut. And that encourages the beneficial acid-loving bacteria and it inhibits the growth of alkaline loving, harmful bacteria. If the bird does not respond to Probiotics, electrolytes, organic acids, or the chicken is otherwise unwell, then I think we're into a bit of a bad situation with the chicken.
The next step would be to give the bird some antimicrobials. If we're going to do it, we want to give the bird oral antimicrobials because we want it to act locally within the gut lumen. For laying chickens, my drug of choice would be Tylain, and I would give that orally at 20 milligrammes per kilogramme body weight for 5 days.
This has got a zero egg withhold. Amoxicillin can be used at 15 milligrammes per kilogramme body weight for 5 days orally, but this would be off licence and would be used under the cascade. If a chicken doesn't respond to antimicrobials, the outlook's very poor, and it tends to suggest something very, very serious going on.
Generally, we're thinking of neoplasia. Neoplasia is relatively common in backyard chickens, and they tend to get tumours in the liver, spleen, and on the intestines. Now in younger birds this can be due to Marrick's disease, but in older birds, it can be due to a range of things, and there's lots of weird and wonderful viruses out there that we believe can cause neoplasia in chickens, but it hasn't been conclusively demonstrated.
My own approach would be if the antibiotics haven't worked, it's probably not a great outlook for the chicken. If the owner wanted, you could go and do ultrasonography, radiography, haematology, or biochemistry, but ultimately you're into a very expensive clinical case, and I think it's a job for an experienced avian surgeon, so someone that deals predominantly with birds of prey. I just wanted to touch on obesity in backyard flocks.
Although you might laugh at the photograph of this cockerill who's a very plump buff warpington, obesity is incredibly common, and I've dealt with a number of so-called welfare cases in my time whereby the animal charity felt that the birds were being neglected, but in actual fact they were in normal body condition. Obesity can make the males infertile, and it can make it very difficult for them to mate with the hens. So you might laugh at that, but that's a genuine problem.
And as I said, if you're varying the diet, you can vary the size of the egg for a hen, leading to egg binding. And additionally, a fat hen with a big egg is a recipe for disaster. I've got a rather horrid photograph for you all to look at.
So you're looking into the abdomen of a chicken, and this bird was presented to me. It was 2 years of age and was dyspneic. I couldn't find anything else wrong with it.
It was in good condition. There was no abnormal sounds and auscultation of the thorax or abdomen. The bird was not pyrexic.
It was eating and drinking normally. So like all good vets, I sent it home on Metacam and I didn't give it any antibiotics because there was no indication for it. The bird unfortunately passed away a few days later, and the owner was very keen to have a postmortem examination done, as was I.
So when I opened up the abdomen, I was greeted by this mass of fat and hopefully you can appreciate all that horrible rich yellow fat within the bird. In the photograph on the right, you can just about make out that at the top, the heart is surrounded by fat, and on the right hand side of the thorax, we've got the air sac which is just full of fat. So the bird had so much fat in its air sacs it couldn't breathe.
So obesity can actually kill backyard chickens. I'm not going to hand you back to Stacey for our 3rd poll question. OK, Richard, the 3rd poll question has now been launched.
So what's the best approach to a hen with mild diarrhoea? Option A, antibiotics, B, worming, C, wait and see. D, feed hard boiled eggs.
E give vitamins. I'll just give you 10 more seconds on that poll question. Some people are still voting away.
OK, I think the vast majority of people have voted now, so I'll close that whole question. OK. So, nobody said the first option, antibiotics.
We had 36% of attendees saying worming. And then 56% same wait and see. Nobody said feed hard boiled eggs, and we had 8% of delegates saying give vitamins.
Well, I'm quite happy with all them, answers, Stacey, in terms of, you know, my approach would be to wait and see, but if the owners are pressing you to do something, worming the bird's fine and giving vitamins is equally fine. The answer I didn't want anyone to give was to feed hard boiled eggs because that's illegal to feed hard boiled eggs or eggs in any form to chickens, and there are people online that would advocate it. There's lots of online forms whereby people can Google that they've got a thick chicken and they'll recommend feeding hard boiled eggs to chickens or indeed milk.
And it's important to remember that chickens cannot digest lactose. We're now going to continue with the digestive tract to look at crop impaction. So in the wild, chickens are prey animals, and they tend to search for insects and seeds on the forest floor.
They gorge on as much food as possible and then fly back up into the tree and digest it. So the chickens have got a diverticulum of their oesophagus known as the crop. The crop is at the cranial inlet of the thorax, and it can vary from a virtually undetectable sack right the way through to the size of a small orange.
And hopefully you'll all appreciate that the chicken in this photograph here on the left-hand side is not a very well bird and has got a massive pendulous crop. This is totally abnormal. But what we tend to find in practise is owners presenting chickens with a slightly smaller crop than that.
And sometimes the chicken can just be very gluttonous. So my recommendation to vets and to owners when you see a chicken with an with an enlarged crop is to fast it for about 8 hours. Typically, a chicken's crop will empty within 4 hours, so I would keep it away from any food, but give it ample access to water.
And generally after about 4 hours, it should have shrunk down, maybe give it a little bit longer, up to 8 hours, provided it's otherwise well. Now if the crop hasn't shrunk back down, then we're in trouble. Again, if you Google crop impaction and chickens, you'll find a whole plethora of different old wives' tales online from tipping the chicken upside down and massaging the crop through to giving it olive oil or maggots.
Ultimately, this is a job for crop surgery, known as an luviotomy. We can see in the photograph on the right-hand side that this chicken is having an luviotomy, and the bird's conscious, so we're doing it under a local anaesthetic, and the bird isn't one bit bothered at all. In fact, it was trying to eat the material being pulled from its crop.
Normally when we do an aluviotomy, you tend to find that there's either an impaction of string or plastic or long straw or grass. So it's really important obviously not to let your chickens have access to plastic or pieces of string and to keep the grass within the range as short as possible. So the first step in an luviotomy is to pluck the feathers off the crop.
If you cut them, they won't be replaced until the chicken necks milk, whereas if you pluck them, the feathers will start to regrow almost immediately. We're looking for a surgical incision, probably of about 1 inch in length. So once we've fuck the skin, we'll do a line block with local anaesthetic.
We will then Clean and prep our surgical site and make an incision first into the skin and then into the crop wall. Unfortunately, no matter how hygienic you are, whenever you incise into the crop a bit like rumen surgery, there's going to be a lot of crap coming out there that's going to contaminate your wound. So try and exteriorize the crop as much as possible.
But I tend to find that this part in the surgery, the chickens don't like it. I think they don't like the feeling of the crop being pulled. Always make sure you make an adequate incision in the crop wall so that you can pull out the material without tearing it.
Once you've removed all the material, You can lavage the crop with some sterile saline and then suture the crop wall up using a simple interrupted pattern with an absorbable monofilament. And again, I would do this skin in a simple interrupted pattern with an absorbable monofilament. Don't let anyone tempt you to use non-absorbable sutures in chickens because their skin heals remarkably fast, and you tend to find that removing the sutures is an absolute pain in the neck.
Aftercare is quite important with these chickens because what you don't want them doing is going and gorging again and putting a lot of pressure on the surgical site, so little and often in terms of feeding them is really important. You can actually get a crop brat online and to stop the chickens from eating too much, so it almost acts like a gastric band to stop them engorging their crop too much. One of the things to warn owners of is that there may be a blockage further distally or alternatively, there may actually be some problem with the digestive tract further distally, which is reducing motility, and I'm thinking of neoplasia here, which would be number one on my differentials list provided that we've removed all the material from the crop.
We're now going to move on to the second half of our webinar to look at postmorteming chickens, and I think that postmorteming backyard birds is a really useful diagnostic tool. Technically speaking, it's illegal to bury backyard chickens at home, so there's a bit of an impetus for the owners to have you to postmortem them. And because of their size, it's relatively practical.
So I would encourage you all to have a bit of a go at it. The first step in postmorteming chickens is to have a check of plumage, check around the vent for pesting or any slice or mites, and under the wings, and have a good idea of overall body condition. Next, place the chicken in dorsal recumbency, as you can see in the photograph.
The next step is to make an incision along the sternum and to peel the skin away, revealing the breast muscle. The chicken in this photograph has got normal body condition. I think the problem is that we're all used to going into our supermarkets and buying chickens for our Sunday roast, and they've got a disproportionately big breast due to their breed.
Most backyard chickens will have quite a thin body condition, so this would be quite normal in the photograph. Next, I try and dislocate the hips of the chicken, and they should pop out to stabilise it so that it's not rocking back and forth when you're trying to postmortem it. Have a look at the colour of the breast muscle.
This again is a nice normal colour of breast muscle for a healthy chicken. Dark breast muscle can indicate either septicemia or dehydration. So you can see in this photograph here, the breast of the chicken is very thin, so the breast, the bone is relatively razor sharp and very easily palpated, and you can see here that the muscle is very injected in bright red, which would denote septicaemia of the chicken.
The next step is to cut along the lateral walls of the thorax and abdomen to reveal your liver, and this is a nice healthy liver of a chicken. As with most species, the liver should fit neatly within the rib cage. If the liver is projecting beyond it, it tends to indicate abnormality.
So my approach, if I'm presented with a slightly abnormal liver, is to take a section of it and send it off for histopathology because it's the best diagnostic tool if you can't diagnose grossly what's wrong with the bird. So what I'm going to do is show you a couple of photographs of some abnormal livers. So going back to this chicken that's septicemic, you can see that the bird's right hand liver lobe is extending way beyond the thorax, and this is in conjunction with septicemia of the bird.
Hopefully you'll also notice that cheese-like material, which is of course egg yolk peritonitis. So that's what's driving the septicemia within this chicken. Sometimes chickens get neoplasia of their liver, and you can see here that this liver is full of white nodules.
In this case, it's Marrick's disease. Potentially it could also be avian leukosis. But again, if you're unsure, I would send a section of the liver off to a histopathologist.
Now this photograph here is really important for you to remember. This is a liver with blackhead, and you can see on the liver, there's these multiple lesions, which are typically 1 centimetre in diameter. In the textbooks they're described as hobnail liver lesions.
And again, if you're unsure, histopathology can confirm blackhead, but this is pathogonomic for blackhead and chickens, so try not to forget it. I think if you're going to remember one photograph from our postmortem slide, I would remember this one. Next, we ought to have a look at the spleen.
So in the right-hand photograph, you can see that we've got the gizzard, and just in under the gizzard, we've got the spleen, which is typically the size of your thumbnail and is a purple colour. If the spleen is either black or very enlarged, it can indicate either septicemia or indeed neoplasia. But neoplasia in the spleen tends not to be multifocal, it tends to be more a diffuse pallor that you see.
Next, we want to have a look at the kidneys. Now just to orientate you, this chicken's in dorsal recumbency. On the left hand side of the photograph, you can just about make out the edge of the heart, and you can see the lungs, and on the right hand side of the photograph you can see where the intestine's been pulled out.
So we're staring right into the abdominal cavity and what we're looking at is along the vertebral column is the chicken's kidneys, and these extend all the way from the causal aspect of the lungs right the way through down to the vent. The kidneys are rigid and they're fixed to the vertebral column, and what you're looking for is any signs of urate deposits indicating dehydration. So in our next photograph, you can hopefully appreciate that there's a very bright white line within the kidney of this chick, and this is a bird that's died due to dehydration, but why we've got urate build up within the ureters.
So I'm gonna hand you back to Stacey for our 4th poll question. Yes, Richard, your penultimate poll question has now been launched. So what's the diagnosis, based on this liver from a postmortem examination?
Is it Marrick's disease, bacterial septicemia, or peritonitis? A diagnosis isn't possible on this gross examination, viremia or blackhead? We've got half of attendees who have voted at the moment, so I'll just give people a little bit more time.
To place their votes. OK. And I'll close that whole question now and share the results.
So, 7% of attendees chose option A, Merrick's disease. Nobody thought it was bacterial septicemia. 4% of attendees saying diagnosis isn't possible.
No one said yemia, and 89% are saying blackhead. So the answer is blackhead as the lesions in the photograph are pathogonomic. However, if you said that a diagnosis is not possible in gross examination, it's not necessarily wrong.
It can be quite difficult. So I think sending a sample off for histopathology is also an equally valid answer if you're not sure. We're now going to move on to look at the respiratory tract.
So in this photograph you can see the lung here, which is a bright salmon pink colour. This is a normal chicken's lung. Pneumonia is very rare in chickens.
Because it's got a really good blood supply to the lungs, a chicken's lungs are rigid and fixed to the rib cage, and in order to get air through the lungs, the chicken has an extensive network of air sacs throughout its body to act like bellows moving the air through the lungs. Part of this feature means that the air moves unidirectionally through the lungs, so air will never pass twice through the bronchi. It will only go in one direction.
And this allows chickens to have a very efficient respiratory system for flying. The downside to this design is that the chickens have got these air sacs. Now a chicken has got 5 pairs of air sacs throughout its thorax and abdomen and a single intraclavicular air sac.
These air sacs are like a sheet of cling film. They are very thin. They have no vascularization, and it means if any bugs do reach the air sacs, it's very easy to cause air sacculitis, and you can see that it's a hop skip and a jump from the air sacs into the abdomen to cause peritonitis.
So any neovascularization, any pus in the air sacs would suggest respiratory disease of the lower airways. So I tend to ignore the lungs and really focus in on the air sacs. We've got the heart here in the pericardium of chickens, and you can look for pericarditis, hydropericardium, and cardiomegaly, but cardiac conditions in chickens are relatively rare in backyard birds and in laying birds.
We can see I've removed the heart here from the pericardium. And when we're looking at the upper airways, the trachea of a chicken should be a nice pale colour, as in this one, and it's on the ventral neck, and the rings of cartilage are complete rather than in mammals where they're incomplete. We're looking for any worms in the trachea or any inflammation.
And we can see here in this photograph, we've got horribly inflamed trachea. Now, it's not really possible to diagnose grossly what's caused this, but I would send off a sample for histopathology and try and find out. And in this case, it was a viral tracheitis.
Next, we can see gapeworms in this photograph. So hopefully you can just about appreciate the the mass of worms blocking the trachea, whereby it's actually causing obstruction and this chicken is choked to death on a mass of worms in its airways. Gap worms are incredibly rare in chickens, but everyone remembers them because they're Y shaped as the male and female are in permanent copulus.
When looking at the upper airways, I want you to make an incision to cut across the maxilla at the level of the nay. You'll have to forgive the quality of this photograph. It's slightly out of focus, but you can just about appreciate that the sinuses are very scrolled, and I want you to appreciate the complexity of the sinuses of chickens because a lot of vets want to do sinus surgery on chickens with mycoplasma, such as the one in the left hand photograph here.
However, whenever you go to start to remove that pus, it's incredibly thick, so you can't just squeeze it out like an abscess in a mammal. And once you get into them sinuses, they're complicated, they're heavily vascularized, and they bleed like crazy. So sinus surgery in backyard chickens is a job for an experienced avian surgeon and a general anaesthetic.
It's not a local anaesthetic job and make a slight incision and pop out the pus. It's a real complicated surgery. Next we'll move on to the digestive tract.
So we talked about crop surgery a little bit ago, and you can see here in this crop that the chicken has been eating some pellets. What I've done here in this photograph is I've removed the entire digestive tract of the chicken. So in the right-hand side of the photograph, you would have the chicken's head in theory.
So we've got the proventriculous, which is the chicken's true stomach. We've got the gizzard, which is an adaptation for birds. We've then got the duodenal loop with the pancreas in the middle, lots and lots of jujunum, and then we've got a pair of siki, a large intestine, and the clowea in the left-hand side.
So we're going to go through each of these parts of the digestive tract one by one. So the stomach, I would tend to open up. And what I've done here in the right hand photograph is I've washed the stomach out, which is easier to see.
So we've got the glandular proventriculus, which is the same as the mammalian stomach, secreting hydrochloric acid and Pepsinogen. We've then got the glandular stomach, which acts like the chicken's teeth, so normally the birds will eat little bits of gritterstones, and the gizzard will grind the stones into the food to break down the particle size, and then the food will move back and forth between the proventriculous and the gizzard, mixing in the acid and the enzymes to break down the food. In the left hand upper photograph you can see hemorrhagic proventriculitis, and this is pathogonomic for Newcastle disease.
It's a very important photograph for you to remember. Next we've got the duodenal loop with the pancreas in the middle. To be honest with you, pancreatic and duodenal pathology is very rare in backyard chickens, and I wouldn't really worry about this part of the anatomy, really.
The dujunum, there's lots of it, and I tend to open the entire length of it looking for worms or haemorrhage or inflammation. But because of the bacterial load within the digestive tract, the intestines break down really fast after the chicken dies or is euthanized, so it can be very difficult to examine the intestinal tract of a chicken once it's been dead for more than an hour or two. We can see here we've got some roundworms.
This is Ascadalla in the jujunum of a chicken, and these worms can be up to 12 centimetres in length and the thickness of a pencil lead. We've got the blind gut or the siki here, and remember from earlier on, I talked about finding Cadbury's caramel in the siki of the chicken. So basically, if you're not finding caramel-like material, then we're going to be looking for blood, which would indicate coccidiosis.
And we can see here that the siki of this bird is full of undigested blood, so it almost looks like black pudding. If you open up these siki, you'll just be greeted by lots of blood. Now this poor chicken is dying due to anaemia, and in some really acute cases, the bird will die due to blood loss before it's had a chance to pass bloody droppings.
So sudden death in very young chickens under 4 months of age could be indicative of coccidiosis, even if there's no signs of either diarrhoea or bloody droppings. We're now going to move on to the female reproductive tract. So chickens have a single active left ovary.
There is no active right ovary and there's no right oviduct. You can see here on the photograph that there's about 14 days' worth of egg yolks all at different stages of development on the ovary, and that's why I recommend when using off-label products in chickens that you've got a minimum of a 14 day egg withhold rather than a statutory 7 day egg withhold. Finally, we want to have a look at the locomotor system.
So whenever we're dislocating the hip joints, we can inspect the normal articular cartilage, which should be bright, shiny, and white, as opposed to what we've got in the left hand chicken in the photograph, whereby the femoral head is necrotic, and this would indicate infection. Joint infections aren't massively common in backyard flocks, predominantly because the birds are a little bit lighter on their feet and also because they grow relatively slowly. But you can get staphylococcal infections and you can also on rare occasions get mycoplasma related synovitis.
And if you weren't sure, either histopathology of the joint or alternatively, you could do some swabs for mycoplasma PCR or swabs for bacterial culture and sensitivity. We're now going to move on to our 5th and final poll question. OK, Richard, I'm just gonna give people more time to have a look at the picture first because last time I was too much of a keen being and launched the poll question straight away and they couldn't see the image, so just give people time to have a look at that and I'll launch the poll question now.
If, if the window is still in the way, you can drag, the poll question window around the screen. If you click and hold, the poll questions tab at the top of the window. Hopefully, a lot of people are voting now anyway, so hopefully I gave you enough time this time to have a look at the image.
Apologies about that on the 4th poll question. OK, so the vast majority of people have now voted, so I'll end that whole question. And, Richard, we've got 100% of people who voted saying coccidiosis.
Excellent. Well, well, well done to everyone. No, and then certainly if you saw Zika like that, coccidiosis would be the only thing that would potentially cause it.
Well, I think ladies and gentlemen, that's it from me this afternoon. I think we've got enough time, Stacey, for some questions if anyone's got any. Yes, we do have quite a lot of questions for you, Richard.
So we'll get started on those, . So Richard, a theme that's been mentioned several times in the pre-congress BVA farm session on the farm session earlier today is increasing engagement for people to be more proactive rather than reactive with health planning. Do you have any advice for engaging health planning activities in backyard poultry?
Yeah, so I think that engaging with backyard owners can be quite difficult trying to be proactive for a number of reasons. They tend not to want to spend any money with you, and a lot of the time they don't really want to do what you're telling them. I think that the fundamentals for me are making sure that there's the selection of a good coup.
I think making sure that the owners feed a balanced diet with minimal traits and making sure that they control red mites and worms. And it's really important to stress that anyone that's keeping backyard chickens should register on the Great Britain poultry register. It's not compulsory for flocks under 50 birds, but whenever we've got bird flu floating around in our wild bird population, I think it's not a bad idea to to sign up to it.
I think the other thing that you've got to be very careful of is where owners are selling eggs to the public. Because once they start to sell eggs through a middleman, and that could be a local shop or a butcher shop, then that starts to bring in a whole set of complexities in terms of traceability and in terms of salmonella control. And so there's a lot of legislative requirements that people are going to be very careful of, and it's all well and good until it goes wrong and someone gets ill from eating your eggs, in which case you've got trading standards, the VLA, and a whole host of people on your back.
OK, thank you for highlighting that to us, Richard. When you were talking about diarrhoea, somebody submitted a question asking if you could repeat the name of the wormer, they didn't catch it. Yes, of course.
It's flubenvet, and that's made by Elanco, and the active ingredient is flubendazole. Brilliant, thank you. And that and that's all in the notes, Stacey as well.
So hopefully everyone will get a copy of them after the webinar, but there's a lot of detailed information in that. Brilliant, thank you. I believe a copy of the notes was emailed to everybody a week before the virtual congress.
So hopefully people have those have access to those now. If you didn't receive a copy, I'm sure if you email the webinar vet team. And they'll do their best to send out the notes to you again.
Someone was having sound issues whilst you were talking about the amoxid dose for diarrhoea. Please could you repeat that? Yes, of course.
So we, we'd prefer that people would use Tylan because it's got zero egg withold, but if you wanted to use amoxicillin, it's 15 milligrammes per kilogramme body weight. And that is given orally for 5 consecutive days. Great.
Thank you, Richard. What local anaesthetic do you use for crop surgery? Generally speaking, I've, I've tended to use lignocaine, but, any local anaesthetic is fine to give chickens, and if you look in your small animal formulary and there's dose rates for the different local anaesthetics, but generally I've never had a massive issue with it.
And sticking on the surgery theme, what is the withdrawal period following drugs used for surgery? Very good question. I typically what you'd find with a lot of these chicken is that they won't lay because they've been sort of interrupted by surgery or the underlying cause.
But again, you would go in line with the cascade and I would put a 14 day egg withhold. Just having a look down. So the next question, what dose of cider vinegar would you use for diarrhoea?
Very good question. And when we get asked quite a lot, and there's no specific hard and fast dose rate for it. If I was using normal off the shelf vinegar from the supermarket, I would probably use about 10 mL per litre of drinking water.
But to be honest with you, my preference would be the owners buy apple cider vinegar designed for chickens, and it's got a recommended dose rate. What you're aiming to do is to take the pH of the water down from about 7 or 6 down to a pH of about 3 to 5. So depending on the strength of the apple cider vinegar, the dose rate will vary.
So it's very difficult buying it out of the supermarket and giving it. It's probably better to go into a local feed merchant and actually buy some apple cider vinegar designed for chickens. Brilliant, thank you, Richard.
Can you save a severely dysic chicken with gapeworm or are you more interested in saving the rest of the flock? Good question. You can try to save a severely dysphonic chicken.
I mean, obviously if you deworm it, you'll kill all them worms, but you're still left with them in the trachea. Now I think if the owner was very keen to progress it, you could try and send the chicken off to an avian surgeon and get them to anaesthetize it, and they can actually insert the The tubes into the air sacs, so they're ventilating it that way rather than through the trachea during the GA and to try and actively remove the mass of gap worms, but it becomes expensive and I think that the outcome of the surgery can be quite variable in terms of saving the rest of the stock. Certainly worming in a flubin bet will work very well.
Or if you want to house the birds as well, gap worms need an intermediate host, such as slugs, snails, or earthworms to complete their life cycle. And if you house the birds, the gap worms can't complete their life cycle, and you don't tend to get a problem with them. Great.
Thanks, Richard. Are there any other licenced or recommended options other than Thailand? I'm not in the UK and macrolides are classified as critically important antimicrobials here, and we're trying to avoid them.
OK, yeah, a very, very, difficult one. I think that in the UK certainly the only zero egg withhold antibiotics for chickens would be Thailand. You've got the option potentially of using The penicillin family.
So in the UK there's another product calledphenoxy penicillin, and that can be used, but I haven't had a lot of success with it. Potentially in other parts of the world. I think about using a tetracycline orally, and I would probably use 20 milligrammes per kilogramme again orally for about 5 days, but I, it would depend on the country's requirements as to what the egg withhold and that would be.
But I guess if you put a 14 day egg withhold, you can't be too far out, I wouldn't have thought. OK, thank you. And why, apple, cider, why not malt or wine vinegar, etc.
Very good question. I think that's just convention. I, I guess in the past people have had a lot of apple orchards in the UK and apple cider vinegar was relatively common back in in the in the olden days, but there's no Logical reason why you couldn't use wine vinegar or you couldn't use malt vinegar simply because you're trying to achieve a reduction in pH using organic acid.
So as far as I'm concerned, it wouldn't make a difference. And on the commercial standpoint we use manufactured organic acids, so it would just be straight proprionic acid we would use. And so I don't think there's any issue with using other vinegars.
Great. Thank you very much, Richard. And we're exactly on time at the moment.
So your timing is impeccable. Thank you very much.