My rooster Jerry has black on the top parts of his comb. I've also started to notice it blistering. I want to help him but I'm not sure what I should do. It's been really cold here and we have good ventilation in the coop. I'm not sure if he got frostbitten or if it was from his coyote attack weeks ago. There were small scratches. He acts normal. He eats and drinks and still crows in th morning. Would Vaseline or neosporin help?