My six chickens all are developing what I think are frost bite marks on their combs. I put vaseline on them today but I'm wondering if I should take their roosting pole down and provide small hay bales for them to roost on at night. Currently their 2 X 4 roosting pole is about a foot below the venting. I've tried various combinations of open and shut vents but nothing seems to do the trick. Would they be warmer down lower? And do chickens HAVE to roost at night? This is our first year with chickens and our Connecticut night time temps are in the teens and 20's. They have about 4 inches of pine shavings on the floor and the coop is a raised one so it doesn't rest directly on the ground. Any suggestions would be much appreciated.