The only bad part about using heat in the coop is a power outage. That's why I use the larger flaked pine instead of sand-it's too cold here (10 degrees last night). A number of articles I read stated that if you're going to use a heat source, you should have a generator for back-up...otherwise you'll loose your birds, as they won't be acclimated to the drop in temperature. As I stated above; I've moved mine to the porch off the garage. They have a plywood box coop with perches and nesting boxes and pine shavings inside, but there's no heat source. There's also no wind. The cement floor outside the coop is covered in straw. It's been below freezing for over a week, and the birds are fine. I do have a heated water bowl, but even if the power goes out, I can keep fresh unfrozen water during the day by continuing to change it out.