No heat, just plenty of food and water. And cover. My "chicken house" is a convterted kennel, I have tarps up on the west side, but didn't always, they seem to do fine, it is covered, but open on 2 sides, one being a not air tight tarp covering. They are eating more than they did before. I did have a guinea before in Missouri that froze to death one night up in a tree, but it was really cold that night, in the single digits and I was never able to get those guineas to go in the chicken house or barn. Once they start roosting in trees, its almost impossible to stop them!