One of my Roosters has a comb that is slowly turning black, or at least it looks like it is. I don't know if this is that Blackhead disease that chickens have. He doesn't seem to have any other symptoms. He is perfectly healthy. He's only about a year old and I thought maybe the blackening was from frostbite during his first winter but it never fell off or anything. And it's more of a faded black. I also have a hen, possibly his daughter, that has a slightly black comb and it has started to flop over. Could this be genetic or is it some sort of disease? ETA: Also the black is only on the back edges, kind of how frostbite would form but it's not frostbite.