I have 5 5 week old chicks m I already treated for cocci about 2 weeks ago all of the others are fine but one of them is not feathering out or gaining weightm all he wants to do is sleep.. He is eating and drinking and he has solid pop but he is weak, I separated him from the others as he wants to stay warmer than the other ones. I just cannot figure out what is wrong. His breastbone is also sticking out.. Thanks for any info any one might have to offer.