Welcome from a former northerner--except I was in NE Ont. We use wood shavings, since that is what we have for the horses. In the summer, sand is great. In the winter, you can shovel the snow up the walls of the coop for insulation, --keeps it nicer. I have heard, (but I didn't have chickens when I lived up north) that if yo udo that you won't need to provide a heat lamp, but can't attest to that, esp at -40C temps.