Wow--thanks for the info cowcreekgeek! I immediately tried adding a little ACV to clean water to see if that helps. I'll also do a big coop/run/water clean tomorrow, as it can't hurt either. I really hope this hen makes it--she is the friendliest hen of our flock, and I'm very attached to all three of our girls!
A little bit of background--we live in western Oregon, so in addition to the water system we have installed in their run, the chickens have access to lots of water. They also run free in the backyard during the day, where we keep an organic lawn and garden. Guessing I can rule out heat stroke, cage layer fatigue, yellow jasmine (and probably algae poisoning given that it is cold and wet here right now), and acute lack of water. Unfortunately, that still leaves some scarier possibilities..
Here, we've had some exceptionally mild days/nights, which would allow for more rapid growth of bacteria, and I have seen flies on some days, and had to plug in the bug light on quite a few nights. And, you're right ... even though the toxins from botulism are among the most poisonous substances known to man, some of the other possible causes of these symptoms are more frightening. But, often, folks feed meat scraps that are no longer fit for human consumption -- if it'll give us food poisoning, it's a potential cause of intoxification. Unpleasant as it is, a dead mouse or mole is often the source.
Two things, in regard to the water system:
- Don't put ACV, or citric acid, or anything else acidic in it if there's any components that acids will damage (galvanized metals, some heating elements, pump impellers/housings, etc. ~'-)
- If you're treatment(s) are delivered via water, you've gotta eliminate any other sources of water, so as to compel them to drink the solution as their sole source ... not usually a problem, w/ ACV or citric acid, as most animals/birds prefer these solutions over plain water.
You can probably rule out a vitamin E deficiency as well, as it most generally affects the young, which show signs of the diseases this may cause, including encephalomalacia, exudative diathesis, and muscular dystrophy. In older birds, there is rarely any outwardly visible symptoms ... the most frequent cause of this, when proper diets are feed, is oxidation of the oils w/in their feed -- once they become rancid, the vitamin E is no longer biologically available to the bird.
You can probably rule out epidemic tremor as well, which is the common name for Avian Encephalomyelitis (AE), as it's also a disease that affects almost exclusively young birds.
That leaves but one disease, for which there is no treatment, or cure ... that's why I suggest you just skip right on past Marek's Disease, and treat this bird for anything/everything else, as you can't even know for certain that MDV has infected any bird 'til necropsy. So, let's just hope it's not that.
Continue the ACV solution. Also, now that she's contained, you can inspect her poop -- looking for signs of internal parasites -- coccidiosis or nematodiasis, for which I prefer treating w/ Amprolium and Fenbendazole respectively. Since even the float test performed by vets can't absolutely rule out worms, and the signs of infestation w/ tapeworms can be visibly seen? I'd treat her w/ fenbendazole, at the rate of 20 mg/kg of body weight for three consecutive days, which is the amount required so as to eliminate infestations of gapeworms as well as all else (except tapeworms). By using this lower dosage than many suggest, this prevents having the bird suffer blockages, or the sudden rush of proteins that killing too many at one time can provide, as the dead/dying worms are digested. Again, as unpleasant as that sounds.
When tapeworms are present, then Albendazole is my preference, and at the same dosage, as this is again the minimum required, based upon the abstracts of many studies.
Despite her being extremely ill, neither one of these are likely to have any negative impact upon her health: Amprolium blocks thiamine, to which coccidia are fifty times more sensitive to than the chicken is, and Fenbendazole has been proven safe at fifty times the dosage suggested.
