Well, my main focus is not for meat, but eggs. I don't have a problem with eating my chickens, just don't do it that often, as long as they are producing. By the time they aren't producing, they can be pretty tough! Even keep the roosters for breeding, unless I don't like their looks or temperament. That being said, this weekend I will be doing some extensive rooster culling, just because I'm getting too many, and the lesser specimens gotta go.
That being said, a sick chicken is a whole 'nother story. If it has a problem that can't be fixed or cured by me, I will put it down just to end it's suffering. I wouldn't eat it if it was some kind of unknown disease, though.
My main focus is the meat. I am getting too many eggs at the moment. Those old hens tender right up in a pressure cooker or slow cooker crock pot, or can them. I haven't got a white egg in a long time, no egg trap nest to figure out who's not pulling their weight on that one, only have one brown leghorn left now and one polish, rest lay brown or green/olive. Have to process some that are laying also to make room for the giants when I start hatching, and a shipment of naked necks. Only going to keep a couple EE/welsummer crosses out of that bunch. Have a few cockerels that are not needed also. We have five kids to feed and have to either cut down on the chickens or the kids, both are expensive to feed Lol!