I have never had chickens so not sure what to do. Stella has been a bit lethargic, stays back away from the flock when they are out free roaming. She seems to sleep a lot, her comb is not perky. She seem reall puffed up in the chest and just stops and sits on the ground. I also noticed she had a poopy butt. The others feathers on their butt are clean. She has never layed a single egg since we have owned her (Stella and Sophie came with the purchase of our home.) we figured she was just old. Sophie lays every day. What should I do to help Stella feel better?