I'm only kinda kidding. When it gets cold enough to freeze, the critters come in. I've had dogs, cats, rabbits, and chickens running around the house at different points, depending on what critters we have.
There aren't any rabbits this year, the cats have the run of the house, the dog is naughty and confined to the kitchen (or a little pen attached to the back porch for out times), and the chickens are divided out between two old rabbit cages and a pet taxi for a very large dog in the bathroom.
Last time there were chickens running around, I only had one. We've got 5 this year, and none of them are particularly people-friendly. (Ille Gal was very people-friendly because she was raised in the house. Put her outside, fox ate her. Very unhappy time.) One of them appears to approve of being in the bathroom, because she gave us an egg this morning.
I'm pretty sure there are all sorts of handy gadgets and such for keeping water warm and not freezing, but what I have is the pop bottle variety, so in they came. I'm hoping to do a little expansion and such once the woodpile is down to nothing bits, Dad takes his stupid log-cutter back to his house, and Uncle hauls his trailer back home. (Why is it all in my backyard? Dad had two ginormous trees taken down about... three years ago. They've been hauling wood and brush out ever since. It's finally almost all gone!) With said expansion, I'm also hoping to arrange for a different type of watering system. Accepting suggestions for something that will stay wet in freezing weather - stuff you've used and like, please, not just heard about.