You can put a submersible aquarium heater in the buckets. I attach mine to a thermoplug so it only comes on during subfreezing temperatures.Good morning everyone! Thanks for the coffee, George.
Karen, I tried using nipple waterers but couldn't get my chickens to use them. Maybe you have to start when they are chicks? I've also tried the cups, which work fine. I liked that the water jug was large and enclosed. But those little cups would get pretty dirty and I had to clean them out every day. Not very different than cleaning out the waterers every day anyway. I quit using them because they froze in the winter leaving the chickens without water at all.
I think @pennyJo1960 has had better luck with nipples.