Case Study Emergencies/Illness Health Issues Necropsy

Case Study: Egg Yolk Peritonitis

Here’s a case sent into me by Bitchin’ Chickens follower Crystal. In the fall of 2019, she took in three two-year old barnyard mix hens. Roadrunner appeared healthy and fit in with the flock. Her only health issue had been a break in her upper beak, which broke again as it started growing out.

Crystal was told her new hen was an Olive Egger, but because she kept a number of coloured egg layers together she wasn’t sure if Roadrunner was laying or not.


In May she displayed the classic symptoms of a hen with reproductive tract issues: isolating herself from the flock, walking slowly and standing upright in a penguin stance. On closer inspection Crystal noticed that she was leaking very smelly fluid from her vent that looked like egg yolk.

Crystal decided to euthanize her and take some photos to figure out what was going on.  This was her first necropsy and she was both photographer and dissectionist.

Upon cutting Roadrunner open, Crystal said that she was full of copious amounts of green liquid (ascites) that filled her whole abdomen. She removed some of the organs for closer inspection and managed to take photos with her gloved hands.

I don’t claim to have much knowledge or experience with necropsy diagnoses. I posted the photos and asked for the expertise from members of a Facebook chicken group.

One of their members kindly gave her opinion:

I believe this poor girl had ovarian cancer and its ‘seeds’ are all over the bowel. There are numerous retained yolks in the ovary as well as hemorrhages and tumours.

There are egg yolks that have been released, but internally laid. There is also inflammatory coating on the bowel which suggests Egg Yolk Peritonitis which would have killed her. If the fluid was green tinged then the tumours must have involved the liver and gall bladder too.

What Is Egg Yolk Peritonitis?

EYP is inflammation in the peritoneum (tissue covering the inside of the abdomen and most organs) caused by the presence of yolk from a ruptured egg or a retained egg in the oviduct. The yolk may result in only mild inflammation and be absorbed by the peritoneum. Unfortunately the yolk is also a medium for bacteria, which can lead to infection. E. coli and Staphylococcus are just two of several bacteria associated with EYP.

Many thanks to Crystal York for her story and photos. All material used with permission.

To learn more about EYP and Ovarian Cancer check out the links below.

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