That poor little chicken has had the worst luck.. at first when she was living in the house she got stepped out by one of the younger kids and squashed flat.. she should have broken every bone in her body but she was perfectly ok. And another time she got attacked by a chicken hawk. Had her back all sliced up and she lived inside for a few weeks while she healed. And now this. Poor girl but she is still doing great. And still laying those eggs. However her flesh does stink quite badly. And i'm not sure if I can do anything about it for her.
Go to the farm supply and get some antibiotics made for fowl, you can put it in the water............ or get something to give that poor chicken. If her flesh is smelling bad, it is probably infected and might end up with maggots in the wounds, gangrene or worse.
Get that poor chicken some help or put her out of her misery. Just because she is walking around doesn't mean she is okay, it just means she is not letting any predators know she is sick and possibly dying.