Wow, quite a few of us here in Gorham, go figure! I'm in Gorham too, on my first year of raising chickens. I have 5 Wyandottes, in a partially insulated coop, with a water heater. I get 5 eggs a day usually, way too many and we are giving them away to friends.
My coop is 8x8, adjacent to a garage, so it has easy power. There is a big cutout near the roof away from the roost, and there is plenty of ventilation- especially with the wind that usually blows up here. I've stuck some foam insulation in front of it to redirect the air so there is movement, but not a breeze through the coop. So far happy chickens, but we haven't had any 30 below days like we had last year.