I don't think he is actually sick, but worry he *could* be a potential reservoir for something that he may be resistant to, but someone else's flock is not. Not sure how likely that really is, but after reading so many posts on this forum from people who got a disease brought into their flock from a free or auctioned chicken, I really don't want to do something irresponsible out of ignorance.
It's still sad, he is so beautiful. The worst part is, my little gray runt, who I think is a female, is really bonded with Big. She (he?) is going to take his absence hard. But this morning I watched him chase the 7 week olds -- both male and female around the yard -- and this isn't behavior I want, and I've got to make some tough calls. I've given myself one more week to make a final decision. Hate, hate this part of flock management.