I wondered if you had a larger coop, and could put in a water heater that would circulate warm water through tubing on the floor, maybe covered with plywood and then pine shavings (or maybe do away with the plywood altogether)...if that would be a viable method to heat a coop in those really cold days. They do it on This Old House all the time. Has anyone attempted that? I can see where maybe if thats all the heat you had, the water heater would freeze up. Or supply lines or something.