I've been lucky so far with the hen's health and it looks like I've now got our first problem (they are just over a year old). I'm just back from holiday and have been out to check the chickens. One was keeping herself separate and not very active. I had a quick look and the only thing that I could see was that she has a mucky bum and was a little hunched over. She came over and drank when I changed their water for fresh and otherwise looks healthy. I've had a quick read and it seems likely to be a prolapse, which is treatable but seems to often recur. We also have one hen that seems to be stuck laying "fart eggs" for several weeks (and don't know which one). Could these issues be related? These are not pets, we keep them for the eggs, so if this one is not laying anyway then I should cull it.
Advice from more experienced chicken keepers please! I'm off now to isolate it and have a better look.