Our temp. here as been unusual, it has been at freezing or just below for about a week. I put a heat lamp in my chicken coop/run to help keep the chickens warm. I noticed that my White Leghorn's comb was turning blue. I was afraid that it was frostbite. I have been putting vaseline on it while it has been cold. I just notice today, that it is now a blueish purble/black. It doesn't seem to bother her. I checked her out, everything else seems to be fine. I haven't noticed her not laying, I have been getting the same amount of eggs daily. What can I do to help heal this? What can I give her? These are pictures I took today.