Black spots on chickens' combs

[Eggcessive]

It would probably be better to have the light on for just 12 hours, say 4-4 or 5-5. They don’t require more than 12 hours of light to lay eggs, and some feel that more than that may increase laying disorders or pecking/feather-picking problems.

 

[CanadaEh]

without seeing pictures I would take a shot in the dark and suggest frost bite. total shot in the dark.

Without seeing the pictures:
1) frost bites are usually on the tops of the combs, while pecking wounds are all over the combs.
2) frost bites are initially pale (like a skin burn), than only turn black after days