All four of my marans roosters have suffered frostbite on their combs after several 8 degree nights. In general, this winter is a tad warmer than usual despite a few nights lower than usual. I am concerned about their fertility at this time after reading this: Here is what Raising Chickens for Dummies says: Roosters with frostbitten combs may be temporarily infertile. But it's not the frostbite that causes the infertility; its the amount of cold that the chicken has been exposed to. Usually fertility is restored after conditions improve and the roosters body recovers from the stress. If my roosters are hot on the tail ,oops, trail of any and all hens morning and again in the afternoon, can I assume that he is fertile and ready to sire the next generation?