Oh, not sweet Coho!I'm so sorry for your loss! Do you know what happened?
Coho started to develop "Marek's eyes" earlier this winter, which had me on high alert. They slowly progressed and deformed her pupils more and more. Two weeks ago I noticed she was starting to lose some weight and was passing some undigested grain. We've been having some nasty winter weather here and driving the two hours to the vet ranged from 'dangerous' to 'near impossible' on the days she had openings. My vet couldn't diagnose or offer advice over the phone (understandably) but also understood my situation and indicated that my idea to treat with flagyl, given Coho's history with c. perfringens, was not a bad idea, so that is what we did. Coho had a good appetite and seemed stable.
Coho's "Marek's eyes". They got progressively worse after this photo was taken in December. Her pupils were fine for years before this.
Last Thursday I noticed she was acting a bit weak and I found a few mites on her. I was alarmed by this; I am a bit of a freak about checking for mites and lice, and I have always used Coho as my 'mite sentinel' because her light colored feathers would make them easier to find. I check at least once a week, all over her and lately also the rooster since he spends a lot of time down low. I've had chickens for four years now and have been, to the best of my knowledge, 'mite free'. I immediately treated her with poultry dust, and brought her indoors, as I couldn't risk her getting wet as she was weak and it's been wicked cold here. (I also treated the rest of the flock and the coop as best I could-- a deep clean and treatment will have to wait until our daytime highs get above freezing).
I knew mites could reproduce quickly but I was alarmed by how fast they reproduced. I think they are Northern Fowl Mite, which can go from egg to blood-feasting adult in two days. I sought the advice of a few knowledgeable members. She ate an entire egg that night and the next day I went out and got some hand-feeding formula to tube her if need be. She continued to get weak (with dead mites raining off of her) and I did end up tube feeding her. But, she was just too weak and it was too late. There was no one to take her to over the weekend and she passed peacefully in her sleep, Sunday night, before we could get her to the vet on Monday morning...
After she passed, the remaining mites vacated her body (as they do) and there were an alarming number of them that survived the treatments. I must assume I have a pesticide resistant mite.
I think it was a combo of things; she was already sickly and unwell, with immunosupression from Marek's disease, and it was just a snowball effect of things against her. I feel miserable over it.
I still don't know how we ended up with mites, all I can guess perhaps on one of the very cold and nasty snowy nights we've been having that perhaps a wild bird tried to sleep against one of the coop vents to keep warm? The chickens haven't even been out in the yard since December. The snow has been too deep-- over their heads! And they have no interest in the paths I shovel for them... I guess if they can't dig down to the grass and goodies, they simply aren't interested.
In happier news... all of the other chickens are doing okay, are strong, "fat" and happy, even Derp. She is very spunky so I am thinking she may start to lay again soon. I am monitoring the mite situation carefully.