I know it is still summer, but I want to make plans to keep my chickens through the winter. I just started raising this spring, so cold weather with chickens will be new to me. I have a tractor coop from Green Chicken Coops, and find it is adequate as long as the chickens can run in an additional fenced in area. I live in Iowa so the winters can get very cold. My chickens are from local suppliers who tell me they are very hardy but what should I expect?