Hello, I have a hen with a dirty bottom with a quarter sized black circle that is raised with an excavated centre. It is smooth and half an inch below her vent on bare skin. Besides that, her bottom feathers are covered in poop. I think it is dried poop, my husband thinks it is a rotten area or abscess. I will try to take a pic tonight but in the am we have to go away for a couple days. Her face, waddles and comb look poorly. Her feathers are in good shape. Might this be worms? This is my second sick hen. I am feeling overwhelmed.