They stand more of a chance of staying comfortable if you leave them in the coop. They are much more acclimated to colder weather right now than warm. Throughout the winter, they have been growing their down coats that they don't get to take off. So, if you take your down-and-feather-covered bodies that are made to trap warm air to their bodies and keep them warm, and put them in your heated basement, they will become too hot and that's far more of a problem than too cold. Just make sure they're protected from the elements, your coop isn't wrapped up tight so they can have plenty of ventilation, and keep changing out their water. I live in MN and we've been having 30+ degree temperature changes for the past couple of weeks. My chickens are fine in their unheated coop. They are much better off cold and dry, than warm and humid.