If you keep quail in an area that is cold and snowy, then always offer them a place to get completely out of the wind, rain and snow. If they can stay dry and out of the wind, they can survive brutally cold temps. If they don't already have a small box or coop to snuggle into, then start now getting them used to it. Make sure this "coop" has enough light and ventilation, and lock them in for a few days now, so that they see it as safe and secure and will figure out that they will stay warm at night when using it. If you don't lock them in, they will never use it. After a few days, they will wander in when it is cold outside or to escape the wind and snow. If you use something with a wire floor, then use bedding over the wire so their feet do not get frostbite. Wind and air from underneath them can chill and kill quail. When a birds feet are cold, so are they. Keep the feet warm and the birds can survive thru winter. Use something that has solid floors, ceiling and sides so that no wind, snow or rain can enter. If it is going to get down below minus 5 or minus 10, use a heat lamp to keep them warm. Otherwise, no heat is needed.