I also think that chickens are acclimated to the climate they grew up in, something folks rarely mention. Mine wouldn't make it in Wisconsin and yours would be partying hard here, thinking they had made it to Chicken Shangri-La (well, maybe not so much tonight, LOL). Maybe the Brahmas and mostly younger to middle aged hens don't need heat at all, but an ailing bird, a naked bird, or one like old Amanda may need a heat spot. It really depends on the situation. And Lisa, you also have other animals in the barn, too, and use the deep bedding as well. You have a really good barn for them to be out of the wind like I do, though yours is larger than mine. I have no larger livestock to provide body heat and we don't do deep bedding, though I piled in some hay with Georgie's group and the other old hens' group tonight.