I didn't heat my coop (my first year with chickens) mostly because I didn't trust the power grid. If the power went out and the girls and boys were dependant on electric heat they'd be goners. I wanted them to be hardened off to the cold. We did make a nice small area inside the henhouse with hay bales and piled hay so they could snuggle in together and keep warmer. They never really seemed cold. They fluffed up to an amazing extent at night when they roosted. We joked they looked like chicken balloons
