Are your cages close together....so that they could still peck at each other? This does look like peck wounds and not frost bite to me. Also, one year I had a roo cut his comb on a wire in my greenhouse, so make sure he didn't get his comb caught on something.
Oh yikes. I was wondering what that was too. My roosters don’t have it that bad just a little sometimes but it makes sense that it’s from pecking at each other. They’ve already determined who is the dominant one so I rarely see it now but for a while I saw it a lot. Now the only one to have it is the cockerel who still thinks he can beat an adult rooster up