Combs have black spots
Your chickens got freeze comb. If you want to protect their combs, put petroleum jelly on their combs each night when they got to roost. Hope this helps!
- The Chiarian
Looks like pecking to me.
Pox could be another possibility but it's not frostbite or else the tips would be dark gray to black as the tips would get frozen first.
My bet is on pecking or dirt.
I thought it was freeze comb since my friends chickens (Mine are easter eggers so they dont get freeze comb) had the exact same thing, except it was on the tips too. Sorry, my bad .