It looks like a cancer. The skin around my little rooster's vent area is a black, crusty scabby, thick mass. I don't dare cut it away because there are blood vessels underneath and where a bit of the mass split, there was a little blood. I have put him in "sick bay" in a heated room and am keeping the infected area cleaned two or three times a day, and dressed with triple anti-biotic ointment. At first he was having trouble pooping, but since I started cleaning and dressing with the ointment, he is not having any issues, and poops normally. This rooster stays in his own rabbit hutch coop, because he is half blind - has been so for years. His coop has pine shavings and with a roost. I keep it clean and he has no mites, lice or any kind of vermin. He is five years old and never had anything happen like that. He is not in physical contact with any of the other chickens in the barn. This is baffling. Any ideas what could cause this? A couple questions I had were that if might be the bacteria that causes bumblefoot, or could it be a form of Marek's?