For the most part, chickens are more cold tolerant than tolerant of the extreme heat we've had in the south this year. Puffing of feathers & body heat from cooping together in snug space for body heat generally takes care of the problem at night. Don't know how far north you live, but if winters are bitter, you'll need to really careful about frostbite on the larger combs of some of the chickens you have. Try this area: https://www.backyardchickens.com/web/viewblog.php?id=7693-seasonal-concerns