Word to the wise, I built the same bucket with nipples and the same stock tank heater and the nipples froze solid, it just doesn't keep the water warm enough, I switched to an aquarium heater and it has worked much better, it keeps the water close to 80 degrees and keeps the nipples thawed, the stock tank heater does exactly what it is supposed to but it just doesn't give off enough heat, mine is out in the run if yours will be inside out of the wind chill it might work out fine good luck.
