Our rooster has developed black sores on his comb as shown below. I believe it's frostbite but it looks similar to the the pictures of fowl pox I've seen in the forums. I am also wondering about pox as our hen also has a couple small black spots. There was a couple nights in the low 20s (maybe upper teens) when we didn't have the heat lamp on. They are out of the wind in their coop but it is large for six chickens (4'x8'). It's my first season with chickens, can someone more experienced help me out?