I've noticed today that 2 of my roosters head (comb) color is different, like dark purplish. Now that does mean a frostbite ? Out here in NJ, it's pretty cold, at nights it can get down to 10's degrees. They have 7x7 chicken shed with 2 big heated lights. We are in the process of building them a new coop at a different location in our backyard. But in the meanwhile, do you think their cold ?