Our coop is about 4'x6', and we have 7 chickens in there. They only use it to sleep in, and as of yet there's no insulation (the walls are plywood, with several openings for ventilation). Since we're in Georgia, I think we probably won't need a heating lamp (even though the verdict is not out on that one, yet - I'm open for advice), but I would like to cover the windows with clear plastic, and insulate the walls with something. What's a good material to use? Also, the floor is just a dirt floor, covered with about 3 inches of wood chips. Is that sufficient to keep the cold out?