Fowl Detectives

chicken

Abstract

Fowl Detectives:  Using Physical Exam and Clinical Signs to Diagnose Poultry Diseases

There are a growing number of individuals that own backyard chickens. These poultry are kept not for only pleasure but also as a source of eggs. In fact, one of the hottest commodities during the early months of the COVID-19 pandemic was the demand for day-old chicks as many individuals wanted to raise their own source of eggs for food sustainability.

Backyard and/or small flock poultry medicine is increasing in demand and the need to serve the medical needs of this animal population are in much demand. There are few courses, if any, dedicated to poultry medicine in current veterinary school curricula, but many veterinarians can further their education by attending continuing educational conferences. Veterinarians can apply their knowledge, skills, and training to work with poultry species.

In this seminar, we will discuss the basic approach to the poultry patient, beginning with the physical exam and the clinical signs observed. It is important to know and understand the clues provided so that an expedient diagnosis can be made to assist client and patient. A thorough history of the poultry patient must be obtained to narrow the differential diagnoses list. In should be mentioned that poultry have unique anatomical differences from mammals, and this will affect the clinical approach in working up poultry cases. In addition, poultry diseases often impact multiple organ systems, which may stump the novice poultry medicine practitioner. This webinar will also review the diseases that should be considered when examining different anatomical structures and the clues that allow the practitioner to develop a differential diagnosis list. Though these discussions, we will review common diseases of backyard poultry that are frequently seen in private practice.

 

Outline

Brahmas chicken JumpV

 

 

 

 

 

 

Orpington

Elias Daniel | Flickr Creative Commons

 

 

Wyandotte chicken

photogirl7 | Flickr Creative Commons

 

 

  • Introduction
    • Tools for the practitioner
    • Becoming a fowl detective to aid in diagnosis

     

  • Physical examination
    • Overall structure and symmetry
      • Body condition
      • Skeletal diseases
      • Feather-related diseases
    • Examining the head
      • Basic exam
      • Eyes
        • Eye examination
        • Diseases of the eye
        • Swelling around the eyes
      • Ornaments
        • Diseases of the combs and wattles
        • Diseases of the snood
      • Oropharynx
        • Exam
        • Diseases
      • Extremities
      • Vent region

 

  • Clinical signs
    • Respiratory issues
    • Digestive disorders
    • Reproductive findings
  • Age and types of diseases
  • Solving the cases

 

About the presenter

Dr. Teresa Morishita is a Professor of Poultry Medicine & Food Safety and former Associate Dean for Academic Affairs at Western University of Health Sciences College of Veterinary Medicine. Dr. Morishita attended the University of California at Davis (UCD) and received a dual Doctorate of Veterinary Medicine and Master of Preventive Veterinary Medicine degree. Wanting to gain additional skills in clinical avian medicine, she completed a residency in avian/poultry medicine from UCD and became a Diplomate of the American College of Poultry Veterinarians. She also earned her PhD in comparative pathology… [Learn more].

 

Webinar recording

 

Post-test

With a passing grade of 70% or higher, you will receive a continuing education certificate for 1 hour of continuing education credit in jurisdictions that recognize AAVSB R.A.C.E. approval.

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Expert Q+A

Although Dr. Morishita answered most questions during the live event, the remaining questions were answered by email and are posted below:

NUTRITION

Is there a right amount of commercial diet to feed or should it be free choice?

Adult laying hens normally eat about a 0.25 lb. (113 grams) per day, which is equivalent to about ½ cup per bird, but I would always suggest that you look at feed labels as they will tell you how much food should be fed per bird as part of the feeding instructions.

Also consider the amount of feeder space, because some of the more dominant hens will eat more than their fair share. Hens lower in the hierarchy might not get enough food. So, make sure all birds have equal time to feed and have enough feeder space.

Another thing that will impact the amount of food offered is access to wildlife. Unfortunately, wild birds will come and eat some of that food, so [the hens] might not be getting their whole supply.  

So, you have to balance all these different factors when you’re feeding these birds.

Editor’s follow-up question:  Do you suggest people assess bird body condition?

Because chickens are so docile, I would [suggest] periodically picking them up… [Owners] can assess body condition and examine birds for external parasites, like lice and mites, because you always want to get a head start on controlling those particular parasites…We want to teach owners how to do this because they are our first line to tell us if something’s wrong and then they can bring [the birds] into us.

 

With grit, can you give an example of a gradual introduction? How much grit? How often?

Normally some people like to sprinkle grit in the food. If you intend to feed grit, begin to offer this item at a couple of weeks of age. If you offer grit to an older bird, they might be attracted to it but they’re not used to it. So then they’re going to overload and some might develop impactions.

Grass impaction is another example of what happens when food items are not offered gradually. I’ve had several cases of people keeping young chicks…Spring comes and they let their chicks out and they are attracted to all the grass because they haven’t seen that before. They engorge on the grass and develop grass impactions.

 

What are the commercial diets you tend to recommend?

Well, you know, as long as you get it from a feed supply company that is reputable, that has been in the business for a while, and is regulated, that should be a feed that you [can] use. Labels should include feed analysis, and [the feed] should be properly labeled for the particular age you’re feeding, whether it’s chick starter or layer diet. That’s the main things that you want to look for.

 

Are scratch grains good or bad, added to a formulated diet?

Editor’s reply:  Scratch grains are good in that they promote normal foraging behavior. They can be offered occasionally by scattering grains on the ground as enrichment. However, scratch grains are bad in that they dilute the nutrition of  formulated diets. Most owners use them not so much for enrichment, but to cut the cost of the commercial pellet or mash.  

 

INTEGUMENTARY

What is [the] molting response for Gallus domesticus [the chicken] that has a reproductive issue (namely enlarged oviduct)?

We do know that chickens that are sick, not eating, or not given proper food, may begin a molting process. So in a bird with an enlarged oviduct that might have salpingitis, this individual might not be eating and potentially it could begin a molting process.

Instead of worrying about molt, the bigger issue is what is causing that enlarged oviduct and to get that treated right away. Because an enlarged oviduct, especially if it contains a lot of debris like a lash egg, that can rupture the oviduct and then you have coelomitis. So, birds with an upright, “penguin” stance should be presented for evaluation right away.

 

How best [to] treat feathered feet with molting issues or ingrown feathers?

For a breed that has feathers on the feet, birds will naturally molt those feathers. There should be no problem because they’re born like that.

We do see problems with ingrown feathers when the feather follicle is damaged and at that point, you need to have them removed because they would just swell up in that area and potentially could cause a local infection.

Are the feet a common area for molting issues to occur, due to trauma, etc.?

No, I wouldn’t say that unless there’s some kind of damage or maybe the owner is plucking off feathers because some owners would want to cut off feathers on the feet, when they become caked in feces for example. This problem can be minimized by having wet grass or something that would not cake up mud on the feet. In addition, debris caked up on the feet can be removed gently if you soak the feet in water to moisten the debris.

[The owner] might actually be pulling out the feathers the wrong way…[W]hen we remove feathers, it should be done in the direction of feather [growth] and not in the opposite direction. The latter can cause some damage to the feather follicle and then the new, growing feather can potentially be ingrown.

So to answer the original question, I would probably say we need to investigate why there’s a lot of ingrown feathers in that particular flock. Is the owner plucking feathers…or somehow manipulating feathers on the foot? Maybe the feet are getting dirty, owners are trying to remove the caked debris…and causing an issue for the chickens?

 

Why may there be discoloration on the skin?

I’m not sure quite what is meant by discoloration, but we do know that some chickens have darker colored skin, such as the silkies, which have black skin compared to most other chicken breeds..

The question of discoloration on the skin may be referring to the naked necks where their skin is not the “normal skin color”, but is kind of thickened and reddened. One of my first chicken cases in my career was a naked chicken with reddened skin… Regular chicken skin is very thin, so if birds are naturally non-feathered, they might have thickened skin in that area, and that may be considered “discoloration” but its normal for these breeds that are “naked” or have “naked” parts of their bodies under normal circumstances.

I have also seen some laying hens that have had reddened thickened vent regions and this is not normal. So, when looking for discoloration, know what is normal for the breed and where that would be on the “normal” chicken.

Discoloration may also arise from disease, like plaques on the skin surface, such as a fungal growth or ringworm.

 

REPRODUCTION

I’m wondering if there is a way to downregulate egg production in hens if they are having reproductive issues or preventatively for aging ‘pet’ hens?

[The gonadotropin releasing hormone (GnRH) agonist] deslorelin has been used by some people, but these implants are not approved in chickens…Since this is a hormone, the big question is:  What is going to happen to that bird? We’re not dealing only with pet chickens and we don’t know what’s going to happen if the owners give that chicken away and somebody eats them. After all, one person’s pet, might be somebody else’s dinner… So as a veterinarian working with poultry species that COULD be food, I wouldn’t even touch a [GnRH  agonist] unless you ask the Food & Drug Administration for consultation. We do know that pregnant women should not be exposed to these hormones, so you’ve got to watch out when treating pets that are also potentially food sources.

 

What about lash eggs?

When we have salpingitis, we have infections of the oviduct and sometimes we have debris within the oviduct and it remains in there. [W]hen you cut into a “lash egg”, you can see concentric rings, which is actually the caseated debris from the oviduct that has a layered egg-like appearance as caseated debris encases more debris and the lash egg “grows” in size.

When you start seeing a lash egg, then you know more than likely that there is salpingitis. The most common bacteria associated with these cases is E. coli.

 

What is [the] molting response for Gallus domesticus that has a reproductive issue (namely enlarge oviduct)?

We do know that chickens that are sick, not eating, or not given proper food, may begin a molting process. So in a bird with an enlarged oviduct that might have salpingitis, this individual might not be eating and potentially it could begin a molting process.

Instead of worrying about molt, the bigger issue is what is causing that enlarged oviduct and to get that treated right away. Because an enlarged oviduct, especially if it contains a lot of debris like a lash egg, that can rupture the oviduct and then you have coelomitis. So, birds with an upright, “penguin” stance should be presented for evaluation right away.

 

OPHTHALMOLOGY

How often do you see that change in the iris with Marek’s?

Well, that’s a very good question, because there are a lot of different Marek’s disease virus strains that differ in pathogenicity. When this herpes virus infects a chicken, some chickens have very different manifestations. There is the peripheral nerve form, which is when we see the “split legged chicken”. We can also have discoloration of the iris or the skin form, which has folliculitis, or there can be internal organ tumors.

How often do you see it? You can observe it occasionally. I had one flock that didn’t have any outward appearance of Marek’s, but when you examined the birds [more closely], some individuals had blue eyes and that irregular pupil margin. I’ve had other [commercial] flocks that don’t have even the neurological signs, but then when they were sent to slaughter, all the birds had folliculitis and of course were condemned.

So you can’t really say because it depends on the strain?

Yes, it depends on the strain and how that virus gets into the bird. It’s an oncogenic virus, so it also has a unique response in the host bird. Some individuals develop internal tumors and they die quickly. That’s why we have the vaccine to prevent the formation of those tumors and prevent death, because most birds will die from the internal tumors.

 

Are cataracts common?

Cataracts can be common. If you had asked this question a long time ago, when most chickens were raised for food consumption, then no, because they were slaughtered at an early age. But as people have backyard pets and birds are kept longer, cataract formation is a possibility.

Cataracts can also form in birds that have nutritional problems, such as vitamin A deficiency. Some people have also said that you can get cataracts with Marek’s disease, but I have not personally seen such as case in my career.

There’s also a disease called avian encephalomyelitis, which usually occurs in young chicks. One of the sequelae to this disease can include cataracts, but because we vaccinate a lot of the breeder hens, we don’t really see this condition in commercial production. Plus commercial birds are not kept for very long, but consider this in your differential diagnosis list for backyard poultry, especially with older birds. It is difficult to determine the vaccination history for avian encephalomyelitis in backyard breeder hen sources unless you know the breeder hen source.

 

Does the cornea clouding with increased ammonia levels appear as plaques or uniform clouding?

With increased ammonia levels, ammonia gas interacts with the surface of the eye so the cloudiness will be diffuse across the cornea. Eventually this cloudiness can become severe and then you’ll have focal areas of ulceration, but initially it starts as a generalized, diffuse cloudiness.

 

ANTIPARASITIC DRUGS

Can fipronil spray be used in birds?

Fipronil is not legal for use in food animals in the US, European Union, and in many other nations. Fipronil was banned because it is extremely toxic to honey bees, and we need bees to produce crops. [Fipronil] also has a lesser toxic effect in humans, causing tingling and other neurologic effects, but in general, it’s not a good thing.

 

Can you tell us how to use fluralaner (Bravecto®) for parasites in the US where we don’t have the Exzolt® product?

I have not used fluralaner because it is not approved by the Food & Drug Administration. When you’re working with chickens, remember, this is not like pet birds, this is actually a food animal. If you use this in poultry you go off-label, but then you’re doing so at your own risk.

And that’s why I included that organic recipe, because it’s organic and it’s been approved.

PyGanic PPT screenshot

 

Ectoparasites are a huge problem for us in New York. Can you treat Knemidokoptes without ivermectin? And isn’t ivermectin an approved human drug? Makes no sense!

Ivermectin is another drug that unfortunately we cannot use, and ivermectin is indeed used in humans.

Editor’s Note:  In fact, ivermectin is not approved for use in poultry because the World Health Organization considers it an essential medication for human health. The development of resistance to ivermectin would be disastrous for human health worldwide and therefore its use in food animals is discouraged.

But Knemidokoptes is a tough one. That’s why you want to catch infestations early.  A lot of people put olive oil or something to attempt to stop the [mites from] burrowing and also emulsify the legs.

Try a PyGanic® [specialty organic insecticide] or pyrethins, anything organic. And that’s why there really needs to be a push for more organic products…

 

What is advised for time before eating eggs following deworming?

Well, that depends on the medication and it necessary to check FARAD.org [or a similar advisory source]. I believe the only dewormer on FARAD right now is fenbendazole. Always consult with FARAD when you work with poultry.

 

Do you dilute pyrethrins if spraying birds?

Yes, but use a PyGanic® and it is found on Extension Fact Sheets for use in poultry. Before there was PyGanic, we used to dilute pyrethrins to kitten strength for birds that had sticktight fleas or sever liceand mite infestations so control the number as we examined them otherwise we would have the mites crawling over our hands and arms when examining the birds.

 

MISCELLANEOUS CONCERNS

Is vent gleet something that needs treatment?

First confirm, that the condition is truly vent gleet. Rule out other conditions. Could it be diarrhea or something else? Vent gleet should just be white, since it is associated with uric acid.

Vent gleet is believed to be due to some type of inflammation at that junction between where the urinary tract meets the reproductive tract. So right now, once birds have it, they have it… So, at this moment, I don’t know how you can treat it because it’s inflammation within the cloaca, so how do we prevent that? That would usually be due to some kind of damage, perhaps egg-related trauma.

 

What is your idea about drug prevention in order to control a high occurrence of infraorbital abscess in an aviary of mixed [gallinaceous] species, [including] pheasant, peafowl, considering Mycoplasma spp. as a causative agent?

So the first thing is, if you have such a big aviary, I would do blood testing to see if there is evidence of exposure to Mycoplasma, to see if they’re positive or not.

We do know that chickens can carry Mycoplasma, especially M. gallisepticum, and not show much signs at all, and really no problem, unless they’re exposed to high ammonia levels or there are other respiratory viral entities going on. But we do know that if you mix chickens with turkeys, turkeys are a little more prone and they’ll have clinical signs of Mycoplasma. So they might have antorbital, also known as infraorbital swelling. Pheasants and peafowl are very similar to turkeys in their reaction to Mycoplasma. So if you want to stop this infraorbital disease, I would be evaluating the flock to see whether they’re positive and negative and really try to not mix your chickens with these other galliforms, like your turkeys and peafowl.

Also, chickens are also a known host for Histomonas, and they rarely show signs. But when you have these other birds, such as the turkey and peafowl, you can have histomoniasis outbreaks. Birds will develop clinical signs and show increased mortality.

We do know that the turkeys, pheasants, and peafowl tend to have similar manifestations or it’s reported that they do, so that’s what we normally recommend that they not be mixed with chickens.

 

What is the benefit shown for treating hardware disease or metal toxicity with chelation therapy for Gallus domesticus if surgery is not [an] option?

Well, for chelation therapy, most of the times we’re using calcium EDTA for zinc or lead toxicosis. Recently in backyard poultry we recognize cases of lead toxicosis, but unlike exotic birds…there hasn’t been a lot of work [on this problem] in poultry.

My question when I read this question is:  What are you treating? Are we sure that we’re dealing with lead or zinc?  Hardware disease, if you talk about cattle doesn’t always have to be heavy metals. Poultry can eat a lot of different things…So, I guess it would be more on an individual basis. So get some radiographs and measure blood levels if you suspect that metal could be lead or zinc, and then, yes, you could do chelation therapy… The other thing to do if you can’t do surgery, is some people use a bulking agent or some people have used grit to help push out that hardware or foreign body item. I guess I would need more information on what “initiated” the hardware disease.

 

You mention feral pigeons in contact with chickens (chooks)…what about domestic (meat) pigeons? Do they pose a hazard to chooks?

Pigeons, unfortunately, can be a normal host for Trichomonas…[W]e don’t feed pigeons to raptors because the raptors, if they eat pigeons, can be prone to trichomoniasis.  The same goes with chickens. Chickens that are in contact with pigeons, wild OR domesticated, potentially can [be exposed] to Trichomonas and come down with trichomoniasis. So, yes, the pigeons raised for their meat could serve as a source of disease.

 

What would cause a keel bone deviation?

An attendee wrote:  Very commonly malnutrition. Owners torpedoing the ration with grains, corn, and other crap [leading to] metabolic bone disease.

Dr. Morishita added:  When we observe keel bone deviation, this is normally seen in the older birds—although we can see it in younger birds that have faced enteritis early on…[W]e see this in the older laying hens that may not have been given enough dietary calcium, not given laying hen diets, and then they might develop cage layer fatigue.

 

When dealing with flying/semi-flying birds (even with peacocks) do you consider it adequate to trim the primary feathers? What technique do you use?

If you are clipping bird wings, you always start with the outer feathers first, so that would be the primary feathers. So maybe the first five or six [feathers]…We don’t cut any of the secondary feathers, which are the feathers closest to the bird’s body…However I really wanted to add:   I wouldn’t recommend clipping the wings of peafowl.

…Peafowl by nature tend to be feral…[T]he majority of their time is spent walking around foraging, looking for food, preening, and males displaying, but they normally are free-living. I believe the question is:  How do I keep them in the enclosure [or at the very least within the facility]?

If you want peafowl at a facility permanently, you need to provide an enclosed cage for them. We see that in peafowl breeders, if they want to breed certain varieties of peafowl, they have to be totally enclosed. Because peafowl by nature are feral; they like to be free…and they need fairly large cages.

If you want to keep your peafowl in an area, a lot of people feed them, and the birds will get in the habit of returning in the morning and evening to get their food…

Don’t some zoos perform de-flighting surgery?

Yes, pinioning would be a permanent [solution].

…So, it’s important for the individual to ask:  What’s your purpose of having peafowl in the first place? If your purpose is to enjoy their beauty, to let them run free, then you feed them. If your purpose is to breed them…then in that case, you have to use caging. And if you wing clip, that’s only temporary because they’re going to grow those feathers out again and you’d have to catch them. The peafowl is a large bird that can be aggressive. They’re strong…So if you just clip their wings, then you would have to restrain them regularly, and that’s going to be very difficult…

Editor’s Note:  For a more complete discussion of wing trimming visit the LafeberVet RACE-approved webinar “Flight Mechanics and Ethical Concerns” as well as the review article “Grooming Companion Birds”.

 

RACE approval

This program is approved for 1 hour of continuing credit for veterinarians and veterinary technicians in jurisdictions which recognize American Association of Veterinary State Boards (AAVSB) Registry of Approved Continuing Education (R.A.C.E.) approval.

To cite this page:

Morishita T. Fowl detectives:  Using physical exam & clinical signs to diagnose poultry diseases. LafeberVet web site. July 13, 2021. Available at https://lafeber.com/vet/fowl-detectives/