I'm startin' to wonder!?.... some of my hens in the past have died..(naturally i'm guessing) but one had an odd lookin rear end .. no feathers and a little swollen looking..? .. now one of my new Buff hens is lookin' like that around her rear end??.. i provide oyster shell for them but doesn't seem like they even touch it.. was worried at the time that i saw the swollen rear that she might have an egg stuck up in there but ?? .. My new Buff has been laying it seems just fine.. is a no feathered swollen bum normal?????