Stumbling/lethargic chicken....what is it!

[mintdeer]

A few days ago one of our rhode island reds was acting sick and lethargic so we brought her inside for care. She was very lethargic, stumbling when walking, difficulty breathing and making a rattling sound when breathing. She wasn't drinking much water, but eating a lot. She eventually died, today, after about 4 days. Now one of my wyandottes is beginning to stumble when she walks- she is still alert, eating and drinking, but has difficulty walking (kind of limping and floppy) and sits down a lot, and has diarrhea. We just separated her from the flock and brought her inside.
I did some research and a lot came up about Marek's disease. However we have had these chickens for at least 2-3 years, and they've never had problems before, until now. It is also coming on just after an unusually big rain, which left their pen muddy and wet. Could it be something related to that?? Any help is appreciated!! Also any ideas on treatment....
thanks!

 

[Eggcessive]

Welcome to BYC. Some of your symptoms seem like coccidiosis, but with a flock 2 or 3 years old, that shouldn't be likely unless you have added a new bird to the flock, or something got tracked in. Egg yolk peritonitis can have a lot of weird symptoms, and is more common in hens a couple of years old. There could be multiple problems with the breathing rattles (rales,) lethargy, and stumbling. I would start by worming them with Valbazen or SafeGuard, put them on a poultry vitamin and probiotics in case of a vitamin deficiency, and to promote intestinal immunity. Make sure they are on a good commercial layer feed with 16% protein, and limit other food to 10% or less. If you lose another bird, a necropsy by your state vet would really be worthwhile to give you an exact cause of death. There are so many things that affect chickens--respiratory diseases, intestinal problems, and the wasting diseases such as Mareks and avian leukosis. Sorry for you loss. Here is a link to contact your state vet, along with a link to read about common diseases:
http://www.usaha.org/Portals/6/StateAnimalHealthOfficials.pdf
http://edis.ifas.ufl.edu/ps044