Are the mites treated and gone? Once they are removed he can fully start to regain strength. Give him some beef and rooster booster in his water. Make sure he's separated because the others will pick on him.
Yeah I fed him beef the other day and he had it yesterday too. I came out to the coop this morning and he's in the coop laying down. All the mites look to Have come to the surface and are dead. He won't move today though. He's breathing though.
So I had a northern fowl mite Infestation and I sadly didn't catch it until it got pretty bad ( feel horrible about that) I have a turken that I separated because he was anemic. I fed him lots of greens and put rooster booster in his water. Yesterday he seemed to be improving not his comb but...