Case Study Emergencies/Illness Health Issues Necropsy

Case Study: Ovarian Adenocarcinoma

Case Study #1: Amber, Easter Egger  Aug.1.17- May.3.20

On April 9th I found an odd egg in the nest box: it looked like the remnants of a soft-shelled egg that had broken and then hardened. The concerning part was there was blood on it. When you’ve got twenty hens it’s not always easy to figure out who laid which egg, but I narrowed it down to Amber, an almost 3 year old Easter Egger. Around that time she started roosting in the nest box at bedtime (I ruled out broodiness).

Abnormal Egg

I started monitoring her: she was always out with the flock, eating and drinking and back to the coop in the evening.  I noticed she had some dried poop around her vent – it was mostly white (urates) and a bit smelly. I cleaned her off and trimmed some feathers to see if it continued.

Outwardly she didn’t have acute symptoms, but I could see she was just a bit ‘off’. She started roosting on the coop floor at night. Over the couple of weeks she seemed a bit slower and less enthusiastic about eating and drinking. I picked her up and her weight felt normal.

On May 2nd, she started to look lethargic and laid down in the run. I saw the area around her vent looked bluish and swollen. When I pressed it was soft. I had given her just over three weeks and there had been no improvement; on the contrary, there had been a slow decline.

I’m both squeamish and not skilled at euthanizing birds, so the following day I asked my friend, Thomas, to help. While he dealt with Amber I walked around their garden and visited with their chickens.

He laid out her body in order to do the necropsy and explain what organs I was looking at. I’m sorry I didn’t have my camera ready because as soon as he cut her open, a copious amount of clear yellow fluid (ascites) sprayed out.

He removed the internal organs and there were tumours all over her intestines and I couldn’t even identify her ovaries. There was no sign of unlaid eggs and both of us were stumped at what we were seeing.

I sent her necropsy photos to Dr Bowes, an Avian Veterinarian/Pathologist at the Animal Health Center and asked for her expertise.  She kindly took a look and said:

“What you are seeing is a reproductive (ovary or oviduct) adenocarcinoma, a neoplasia unrelated to Marek’s. The little nodules on the intestinal mesentery are transplanted tumour cells that have broken off from the primary tumour, floated around in the abdominal fluid and attached along the intestine, growing into independent tumour masses. Common in older laying hens. Nothing to do differently.”

I spoke to Dr Bowes about another matter the next day and asked how long she thought Amber had been sick. Judging from the size of the tumours and the amount of damage she thought only a matter of about 3-4 weeks, which fits in with when I first started to see something amiss. One piece of advice she gave me was to not just lift up a bird to gauge their weight, but to feel their keel (breastbone). It should be padded and if it’s sharp that is an indicator of weight loss. The fluid retention from her ascites counterbalanced her weight loss. Had I done a more thorough exam and felt Amber’s abdomen I would have discovered it was soft and squishy.

Case Study #2: Ruby Gold-Laced Wyandotte  July.15 – April.5.17

The next case is actually my first experience with Ovarian Cancer.

In 2016, I was given an 18 month-old Gold Laced Wyandotte. Her previous owner, who had had her for nine months, said she had only ever laid a handful of eggs. In the four months I had her I don’t know if she ever laid. She appeared healthy (beautiful feathers, red comb), ate, drank and fit in with the flock.

One day I saw her in the nest box and was excited that she was finally going to start laying. My optimism was premature because later, when I went to check, there was no egg. The next day she had the classic ‘penguin stance’ of an egg bound hen.

I did an internal exam and found no sign of an egg, so I wondered if she was had a reproductive tract issue. If so, her prognosis wasn’t good. I put her in the infirmary for a couple of days and when it was clear she wasn’t getting better I decided to euthanize her.

Thomas culled her and took some post mortem photos of what he found. She’s the one on the right.

Two years later I met Dr Bowes at a workshop and asked if I could send her some necropsy photos for a diagnosis. She obliged and responded with this:

“She had a classic Ovarian Adenocarcinoma. The hard white nodules are pure tumour and the dark things that look like fish eggs are aberrant ovarian follicles (ovarian tumours can produce some weird and wonderful stimulatory hormones). The fluid buildup and the progression of the tumours isn’t very rapid and would have taken several weeks, even months to develop.

It is not infectious, but is commonly seen in mature laying hens. Nothing can be done to change the ultimate outcome. I don’t think it starts out as painful, but as fluid fills the abdomen it starts to compromise the birds ability to move air through the air sacs and breathe. The tumours also produce compounds that break down muscle tissue, which is why she became so thin.  Mystery solved!”  

This brings up the topic of euthanasia. Dr Bowes suggested that if a bird hasn’t shown some clinical improvement after 24 hrs one should consider euthanizing them. I responded that I was equal parts coward and optimist, and like many people hold out hope and wait too long. Certainly in Amber’s case there was no improvement at all and I wished, in hindsight, I had made the decision sooner.

Remember that hens are bred to lay an inordinate number of eggs. When we push them to lay more (using lights) or bigger eggs or celebrate double yolkers or complain they are slackers when they take a break, we are contributing to all kinds of health issues related to their reproductive systems: prolapsed vents, egg binding, internal laying, egg yolk peritonitis and ovarian cancer.

Be happy with the eggs your hens give you and cut them some slack. Try to buy and breed heritage birds that mature later and lay fewer eggs, but live longer, healthier lives. Chickens are great at hiding their symptoms and although resilient they are vulnerable to all kinds of terminal illnesses. When their time comes try to be decisive and not prolong their suffering.

1 comment on “Case Study: Ovarian Adenocarcinoma

  1. Well-written and well-organized information is always helpful. Thanks for publishing it.

    Liked by 1 person

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