I get together with my mentor Dr Vicki Bowes, avian vet/pathologist throughout the year to look at chicken health issues that I’ve come across and store on a memory stick. She does her best to point out what’s going on with those birds and comes up with the most likely (and sometimes definitive) diagnosis. A couple of times I’ve mentioned having experienced a recent loss in my flock and each time she asked if I brought the body, or at least froze it, for her to look at. It feels a bit presumptuous to expect someone who works in the field to do a pro bono necropsy, but she assured me she was happy to provide the service as a learning experience for both my readers and me.
After that I started freezing specimens. The only problem was I had four losses in five months and hadn’t seen her at all during that time. The last death was from a vent prolapse so I just kept the first three, which we worked on last week.
As a bit of a backstory, Dr Bowes works as an avian pathologist for the Ministry of Agriculture in the lower mainland of British Columbia. I live on a small island two ferry rides away; her future retirement home is here as well. We get together when she’s here, which sometimes makes me feel a bit like I’m cutting into her time off or asking her to do the same kind of work she does week in week out at the lab. As it turns out she really loves what she does and by the end of the day I felt like I should be charging her for the entertainment value my birds brought her. All kidding aside, we had a good time and again, I learned a lot just by watching her perform.
We opted not to work in her home-based lab, but set up an exam table on the tailgate of her truck outside in the sun. She didn’t have access to her microscope and it turned out no diagnostic tests were required. Unfortunately, in all three cases the cause of death became abundantly clear.
Betty, Barnyard mix (Easter Egger, Appenzeller Spitzhauben, Sillkie), 5½ months old
I donated some of my eggs for a school incubator hatch, which were later returned to me as 15 ten day old chicks. They were raised in a large enclosure that contained nine from another clutch hatched and raised by a broody hen, all the same age. All the cockerels were rehomed by four months, leaving 14 teenaged pullets. There were no obvious health issues amongst the lot of them.
In November we had a particularly cold snap so I was out there several times a day bringing fresh water and knocking snow off the tarp over the enclosure. Because the days were shorter I often didn’t see my birds until the weekend (they got up after I left for work and were in bed around the time I get home). I found Betty dead in the coop at the end of my workday. No signs on her body of injury. She hadn’t laid an egg yet.
Before Dr Bowes cut her open we observed a full crop and a prominent keel, noting that she was super thin. There was also build up of a lot of poop outside around the vent. Bursal tumours can prevent the ureters from emptying properly leading to accumulation of fecal matter.
Cutting Betty open revealed a massive liver full of tumours. When I suggested I’d seen worse, Dr Bowes corrected me and said, “No, you haven’t”. She then went on to use the adjectives ‘award winning tumour’, ‘spectacular’ and ‘first place ribbon’. When your pathologist uses such superlatives you know it’s an interesting (and, therefore, not good) case. On a scale of 1-10 for damage to the liver Dr Bowes ranked it a 10, saying it was five times the normal size. She went on to note that the spleen, kidneys, heart and bursa of Fabricius were also affected. Due to the age of my hen and the involvement of the heart, Dr Bowes confidently attributed cause of death to Marek’s Disease.
Splash, Barnyard mix (Easter Egger, Appenzeller Spitzhauben, Sillkie) 6½ months old
Before I had the time to process the first diagnosis we were on to bird #2, Betty’s half-sibling. Splash had started laying beautiful green eggs at 17½ weeks, which is very young for my birds and then stopped a couple of months later. I attributed this to the shorter days. Again, we were experiencing a particularly cold snap so I was home more and out checking on my birds several times each day. I went out at 8am to open the coop and give them fresh water. I was back again with water at 10am and noon and didn’t notice anything amiss.
I returned at 2pm and noticed Splash was on the ground paddling her legs, which I mistook for dust bathing. When I approached she didn’t get up. She appeared to have difficulty moving and was weak. I swaddled her in a towel and put her on my computer desk while I worked. When Splash got fidgety I crated her by the woodstove. Within minutes I heard her flapping wildly against the crate as she had a seizure and then another. She died within an hour of me bringing her inside.
When Dr Bowes placed her body face up on the table she noted that her abdomen was distended, a sign we were going to find something interesting inside. When she opened her up Dr Bowes got more excited than with the previous necropsy and said this case was ‘even better, more spectacular and would be considered award winning’. Not the things a chicken owner wants to hear, at least, not in this context. An examination of her abdominal cavity revealed her ovary had regressed and there were tumours that involved her ovary, liver, spleen, kidneys and bursa of Fabricius. Déjà vu, another case of Marek’s Disease.
Corazon, Appenzeller Spitzhauben x, 4 years old
I knew before Dr Bowes started the necropsy that Corazon’s cause of death would not be Marek’s Disease, since it most often affects young birds (either at 8-10 weeks old or around sexual maturity/point of lay). Dr Bowes had previously necropsied my hen Pixie, who at 21 months, was the oldest bird she had seen with Marek’s Disease.
I had thought Corazon was looking a bit slower in the two weeks prior to her death, but every time I approached her she moved off and didn’t appear lethargic or isolating from the flock. I saw her eating and drinking and otherwise behaving normally. On her final day, I found her in a nest box and not roosting at night, not a good sign as it usually means a bird is having difficulty getting up that high on their own. I lifted her on to the roost bar and in the morning she was dead, just under where she had gone to sleep the night before.
Upon opening her up, Dr Bowes found black post-mortem staining called melanosis on her liver, which is normal, and not a sign of liver disease. Her gizzard was normal and there was a healthy amount of fat. There were adhesions between her oviduct and her intestines. She also found inconsequential, unrelated tumours called leiomyosarcoma (smooth muscle tumours) in the mesentery of the oviduct. They would not have killed Corazon. The culprit, it turned out, was her oviduct was full of inflammatory exudates, a sign of infection. Dr Bowes suspected E.coli, but would need to culture it to confirm. Regardless, it was some form of bacterial infection, which led to salpingitis (inflammation of the oviduct).
It’s a bit odd having the dubious honour of presenting two hens with the classic and spectacular symptoms of Marek’s Disease. Somehow we’d like to think of our birds going quietly and painlessly to sleep and never waking up. Dr Bowes thought this level of damage could occur quite quickly, maybe even in a matter of less than a month and that tumours can grow so fast that they outstrip vascular (blood flow) support.
Dr Bowes emphasizes that all chickens carry the herpes virus and some strain of Marek’s Disease. Some flocks will experience devastating losses or others, like mine, occasional casualties. I lost my first birds (three confirmed by necropsy, three suspected) to Marek’s in late 2019- early 2020. No losses in 2021. Then two confirmed cases, both young hens, in 2021. These are my first losses for 2022, again, both young hens. The rest of my flock, including their hatch mates, is all symptom free.
I have worked hard to reduce stress in my flock which is a trigger for underlying pathogens to become symptomatic: providing lots of space so there isn’t competition for resources (food, water, nest boxes, roost bars), no changes that would affect flock dynamics such as adding new birds (except chicks hatched here with broody hens), offering proper nutrition, and treatment of internal and external parasites.
I asked Dr Bowes if it would be safe to give my hens to the wild bird population that frequents my property: ravens, vultures and eagles. She said they would not transmit any pathogens to them, but we did remove all traces of the salpingitis to avoid any transmission of a bacterial infection. The scavengers made short work of my hens; by the next day all that was left was a pile of feathers.
Once again, my appreciation goes out to Dr Bowes for generously sharing her time and expertise to further my knowledge of small flock health issues. I try to pass on everything I learn hoping to improve the overall health of small flocks everywhere.
The photos are excellent. Thank you both. It is good to have healthy tissue and organs shown as well. Thanks again.
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We were working in the direct sun. I was squinting and my camera preview screen was overexposed so I’m relieved that there were some good photos. Next tailgate party we’ll be in the shade.
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Wow, Claire! You’re doing such a great service to the chicken keeping community! I’m so glad you found Dr Bowes.
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Thanks very much. The lengths you go to educate yourself and us shows such astounding chicken love.
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