This is my first winter with chickens and I do not live in a particularly cold climate but I am worried that one of my girls, a red star chicken named Gertrude, has a frostbitten comb. I'm not sure, I've never really done this before. Any help or recommendations would be greatly appreciated. Thanks! Here she is. It's the black stuff towards the back of the comb that I'm worried about. She wouldn't let me get a better picture.