My 8-month-old RSL hens have beautiful large red combs. Today I noticed dark patches on some of them. The temps here (CT)have not really gotten extremely cold yet, but did drop below freezing a couple of times. Could they have frostbite this early in the season? Their coop is dry, with storm windows but still plenty of air movement, I think. I am planning to Vaseline the combs--any other ideas?