I do brood outside in winter, but I do not use my heat plate to do so because the one I have is not rated for those temperatures. My heat plate is for the indoor brooding of those that need a little extra TLC or, the first day or two after shipped chicks arrived so I can make sure everybody is doing well, or, this year, the first few days after hatch for the eggs I am incubating. I do use it outdoors when I'm not doing winter chicks go to for those cold winter broods is the mama heat pad...