It was said in an earlier post that, "Animals don't heat each other, nor do they heat their coop."
I haven't even read this entire thread yet, but the first sentence of the post above needs addressing.
WORD TO THE WISE
If animals don't heat each other, then why do quail circle up in the winter to keep warm? Ever seen that? I have. Was in a tree stand deer hunting one day and had 23 quail directly underneath my stand in a storm producing "BB" size sleet. Those quail were huddled in a circle, all facing outward, with one bird in the middle of the circle. Each outside bird was backed up against the bird in the middle and each outside bird in the circle was doing a little dance. Why? Generating heat by moving. As I watched, these birds were trading places, each taking a turn in the middle to warm up. There ended up being about 2" inches of little sleet balls on the ground and those birds survived the storm by circling up and keeping each other warm...in the wide open woods.
Animals can indeed keep each other warm. Too many animals, of any kind, in too small a space can cause over heating of the animals within the space and animals can indeed die. I've heard of prized waterfowl dogs dyeing from this very thing on many occasions.
MORAL OF THE STORY
Give animals ample room for their needs and they will take care of keeping each other warm. Just like baby chicks move closer and further from a heat source to keep warm.