I would suggest that you add more ventilation. You never posted the deminsions of your coop; I am very concerned that a LOT of moisture is building up in your cool when all of your chickens are in there.
Warm, moisture laden air has the potential to make your chckens prone to frost bite and respiratory infections. Not to mention ammonia build up. Edited by enola - 2/15/16 at 6:54am