I live in area that is about an average of negative 15 every day, and significantly colder at night. They have an insulated coop and run, and do generate enough heat. I change what's in their water dish 3 times a day, With warm water. Once before I go to school, usually between 6:30 or 7:00am. I change the water when I get back from school, about three pm, and once when its just about dark.
Good luck