I'm guessing this is a fungus or disease of some kind? My 3 Leghorn hens have a little bit of black scab-like stuff on their combs. It's been that way for months. Just yesterday I noticed my EE roos has a lot of black on his otherwise red comb. The 2 EE hens in this flock don't have any black. They have all been together since babies in March. Will it spread and should I treat it? What is it?