My cuckoo marans roo has had this sore for a couple of months now. he has the same identical sore on the other side of his comb, almost like someone shot him with a small caliber gun or something. However, I know that this did not happen to him. There are no kids (or trigger-happy adults) living anywhere near the area. It is a sore. All of my hens' combs are perfectly fine. What's going on with him?
It could be favus. If it is, an anti-fungal cream (athlete's foot cream) should work. https://www.backyardchickens.com/forum/viewtopic.php?id=33925
My rooster has something like this too from when he got in a fight with a wondering roo. He's had it over a year but it never grew any. It only bothers him when the hens pick at it. I'll have to give the cream a try.
