Case Study Health Issues Necropsy Pathology

Avian Pathology Cases: 16

This series is the product of my on-going partnership with Dr Vicki Bowes, avian vet/pathologist. We meet up regularly, me with a flash drive in hand full of cases that are looking for a diagnosis. She often refers to our detective work as ‘best guess’ given that we are often working with insufficient data and photos. I’m impressed with what Dr Bowes is able to achieve and hope that we are able to bring a science based approach to small flock health issues and share it with a wider audience.

Follicle Blisters

My hen presented with lethargy and hot, swollen skin. After she passed, I plucked her underside and found sores all over her skin. She died within 24 hours of my noticing her symptoms. All the white spots were like swollen blisters which you could peel the skin off with no bleeding. – Gaby Deetch

Dr Bowes: It would be helpful to know the age and breed of the bird. The cutaneous form of Marek’s Disease most commonly affects young birds and is rarely seen until the chicken is dead and plucked, as their feathers hide it. I would rule out folliculitis (inflammation of the feather follicles), squamous cell carcinoma and Marek’s Disease. It appears to be proliferative in nature which might be a fungal infection or a neoplasia (tumours). An accurate diagnosis would require microscopic work.


My two-year-old production red hen had ascites (water belly), which I drained once. She was walking slowly with a waddle, had decreased appetite, thin keel and distended belly. She passed naturally. – Kelli Anderson

Dr Bowes: The hen was very thin and had tumours in her liver and oviduct. She also had a huge recent blood clot as well as evidence of older blood clots. Diagnosis: Adenocarcinoma

Suspected Leukosis

We have a Marek’s positive flock and have lost probably ¾ of our original birds. We added 8 new vaccinated hens in February. One of them had the typical symptoms of being egg bound. She just reached maturity so I gave her a soak and felt a big, hard lump right below her vent. She ended up passing and we did a DIY necropsy to see what the lump was. – Jeni Hall

Dr Bowes: That mass is made up of a combination of urates and an accumulation of hardened poop (fecalith) caused by dehydration. There’s something impinging on the ureter or the bird was unable to pass urates. It would have been helpful to have had a photo of the cross-section of the mass to determine whether it was just dried urates or a soft tissue tumour. The bursa is right behind it and may have a tumour in it, which would be rare in Marek’s Disease. Even though you’ve had Marek’s in your flock I would look at ruling in/out Leukosis.


My 7-year-old hen has a large lump on her abdomen above her vent. It’s very soft and hot to the touch. I’ve tried expressing it and nothing came out. – Kimberly Jones Wilkins

Dr Bowes: I’ve never seen anything quite like this. The presentation is odd and doesn’t look like squamous cell carcinoma. Perhaps it’s a reaction to a foreign body. You could treat it like an abscess: wash with an antibiotic soap, soak in an Epsom salt bath and apply a warm compress. A vet would cut, clean and sew the wound closed. The black spots on her feathers are exudate which could be cultured. A 10-day course of antibiotics is recommended.

Oviductal Hemorrhage

Identification please. I found this in the nest box. Four days later, all of my hens are acting completely normal. I have four 2+ year old ISA Browns, two of which have a history of laying lash eggs. This mass had a single egg yolk inside, did not stink, and was firm but not hard. There was no shell or anything else in the nest when I found it. An online group said it was an ovary but I have never heard of a hen laying her ovary. I have searched all my books and the internet and can not find anything that looks anything like this inside a chicken. Any ideas? – Kristine Medlin

Dr Bowes: The discolouration is indicative of a hemorrhage. I think that there was a bleed in the oviduct at the time the egg yolk was being formed and it became enclosed in the membrane. It was just coincidental timing that the two were bound together. The oviduct is vascular and she ruptured a blood vessel. It’s a probably a one-off event, not traumatic and survivable. It’s similar to a lash egg (salpingitis) with a hemorrhagic component.


We had chicken with this lump (hernia?) on her for the last few months. She’s never acted sick and it never grew. We left it because of that. Today one of my other chickens pecked it and this started coming out. I took her out of the coop as soon as I saw it. She was bleeding so I euthanized her. -Melissa Earl

Dr Bowes: It’s hard to know if the lump was a hernia or not. If it was it should have felt soft and you could have pushed it back inside the body (although it wouldn’t stay in). Abdominal tears (hernias) are unusual in chickens. This is a case of cannibalism in which your hen was partially eviscerated.


Exudate: a mass of cells and fluid that has seeped out of blood vessels or an organ, especially in inflammation

Fecalith: accumulation of hardened poop

Folliculitis: inflammation of the feather follicles

And that wraps up this edition of ‘Best Guess’.

I offer my ongoing appreciation for Dr Bowes’ willingness to share her expertise to improve the care of small flock chickens. I’ve learned lots about poultry health issues and I hope that you have too.

If you’ve got an interesting health issue you’d like to share or have diagnosed please feel free to drop me a line using the ‘contact’ button on my home page.

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