I have a production Red roo that has for some time, lost his outer feathers from the mid back down, he isn't bald, he has down feathers, no tail. Only Roo, Gold Sex link hens that don't bother him. Today, I went to feed, and he was sitting, like a hen on eggs kind of sitting. Never seen him do this. I went to pick him up and he got up to avoid me, but couldn't walk, really limpy. I did pick him up and he fussed, but let me look him over, No mites, clear skin with pin feathers,etc. I set him back down, but again, he couldn't walk. I put him in the yard and he did eat grass I picked, but didn't stand. I got him up on his feet and they don't look right, but I can't pinpoint why. He was thirsty and drank water that he limped over to, but has a bad time getting around, just wants to sit. Any reasons or advice? I'm a novice on poultry, so I don't know much. I have cephalexin and injectable penicillin in my fridge, but don't know what is wrong, so I don't want to give him the wrong thing and kill him. He is an exceptionally well behaved roo and I don't want to lose him.