Thanks so much for all your responses and suggestions. Sounds like coccidiosis is a major suspect - one question though, they are on feed that is already medicated for coccidiosis prevention - is it still possible for them to get it?
I have had coccidiosis in chicken chicks before (who were on unmedicated feed), it was extremely contagious and the entire group of chicks all came down with it within the same day. Right now, all my other peachicks still appear perfectly healthy.
Last year I lost 2 peachicks to cocci and a third was saved by a visit to the vet. they were housed with 7 others who never got ill from it. All were fed nothing but amprolium medicated chick starter. I found out the hard way that the medicated feed doesn't cure coccidiosis, it just keeps the little buggers in check while the chick builds up a resistance to them. Cocci is everywhere in your soil, you cannot prevent infection, the trick is to keep them alive long enough to become resistant. Tube feeding is a must, my vet told me the cocci will cause them to not eat and they can starve to death in a matter of a day or 2. Vet also said that something probably caused them to go off the feed just a bit in the first place, but it was enough that they were not getting the adequate preventative dose of amprolium, keep them on the medicated feed and use the corid in the water, I have chicks the same age and one of their favorite things right now is eating each others poop
