The ideas I see on here that I can afford are only good for those decent above 0 or slightly below temps. I have two coops and attached pens and can't afford 50 dollar waterer for both. For the most part, having the coops with deep litter, straw, and all those pesky gaps and cracks around the doors and windows sealed, I just worry about the nights when it's 20 to 30 below and the birds combs and wattles are at higher risk for frostbite because they get dunked in the water bowl. I lost my gorgeous cream legbar roo to frostbite last year. I want to ditch the bowls, but can't afford anything better, and I'm at work too long to keep running warm water out for something that isn't heated. I'm learning quickly to pick better breeds.