I have owned pet chickens for years and have never had a problem until now.... My babies are 6 months old, they have a nice large chicken coop and a huge enclosed run. I noticed a couple weeks ago some black markings on a few of their combs, I thought maybe they scrapped them on the fence or something, but it is spreading on all the chickens... It starts black and then turns gray. It is covering their combs their eyes I have no idea what it is or what to do ..... Am I going to have to put them all down??? One of their combs looks all deformed and has turned all gray I am so upset!