I have a hen that a lot of times has a dirty bottom...... it has recently gotten worse so I washed her bottom.......and to my surprise and horror she has a spot below her vent that looks to be a size of a quarter that looks worse than a sore that has maggots coming out of it!! The spot is black!! She is eating and drinking and acting fine..... only thing unusual is her comb is wilted and her feather are dull. I know I have to get all the maggots out but what do I do about the black sore?