We live in Iowa where it averages 80-90 degrees in the summer and they have been allowed to free range during the day. (8am to 8pm) with no restriction. We noticed in the morning they are dying to get out of the coop. However what should we expect in the winter? We average 5-15 degrees with snow? Will they be ok being locked up in the coop? Or should we still let them out? We plan to get some heating for the coop floor but if we leave the door open then it will be hard to heat..