Brown crust on Hen's comb

[tiffanymedina]

I went outside today and realized one of my hens has a brown crust on her comb. None of the other hens have this crust. They roam the yard and do not stay in a coop often. I am not sure what would cause this or why. Can someone please help me? What is it? What can I do to help get rid of this crust? How can I prevent it from happening to the other hens?

 

[Eggcessive]

There are several conditions that this could be--favus or fowl pox, or maybe something else like a peck wound. If you could post a picture, it sure would help us to help you. I have included 2 links to show you what favus and fowl pox look like:
https://www.backyardchickens.com/t/...wattles-overtaken-by-white-growth-please-help
https://www.backyardchickens.com/a/avian-pox-how-to-treat-your-chickens-for-avian-pox