Every night, my girls go up into there coop around 6, that's when it gets dark here in MI right now, and I fix their newspaper, but some extra straw in their egg boxes, and clean out their food and water and give them fresh. But for the past few days, there water has been frozen! I don't get this at all, because I thought my coop was really well built. I only have 5 Americanas, so their coop is 4x4. with 2 egg boxes and a small window. I do have a light bulb in there, just so they would be warm enough. The bulb is a 250w infer red, and i sometimes keep it on during the day, like today when its around 15 deg. out, but I always turn it off around 8-10 pm. My coop is insulated, and I thought chickens create like, 10 deg. of their own heat. So I don't know why my coop is under 32 deg. Please help, I don't my girls to be freezing cold at night. Thanks!