Last night we noticed black marks on the head of our 2 turkeys - there are more on one than the other. It is very cold here and I wonder if it could be frostbite or if it is something else like fowl pox. I am worried that their shed is too cold and that maybe they haven't gotten enough exercise. It was very cold today so we did not let them out of the shed. They have a small pen approximately 10 ft x 5 ft attached to their shed. What should we do? Thanks for the help.