I just realized one of my chickens was smelling terribly awful then looked at her bum and it was all matted and gross. Then I looked closer and there was this yellow crusty stuff stuck to her bum. then I went to clean her off and found a chasm of worms/maggots inside her skin!!! It was the grossest thing I've ever seen! What is it???? Help! I am keeping her away from the other chickens for the moment but I really have no idea what to do. Any insight advice is desperately welcome.