One of my buff orpingtons has the same thing, just noticed it yesterday. Not crusty though and not really comb, its the ear i think, skin on side of head/neck? Anyways, the skin like turned white or rather is a mix of pink and white now instead of pink. I'm not sure why and interesting the Orpingtons have it.
I thought maybe it could be anemia? I think I have scaly leg mites in my flock and have been meaning to treat so I'm going to try treating that and seeing if that helps. I sure hope it does. Should be pretty simple, just some Vaseline or vegetable oil on the legs to suffocate them then maybe gently washing/rubbing their legs with warm water and some Dawn soap to rub the crust out from between the scales. I hope it works. I'm gonna put some on the comb too just because
