My Buff Orpington rooster's comb is black on the tips and his wattles are showing some discoloration on the tips also. Is this a sign of frost bite or is something else wrong? It's been in has been pretty cold here in northeast ohio, with temps on the minus side. I have a heater in the hen house that I just use when it gets really cold. Any feedback is well appreciated, this is my first winter with chickens!