I hang a 5 gallon bucket from the ceiling with 4 watering nipples on the bottom of the bucket. I have a water heater in the bucket but the nipples freeze and the chickens cannot get any water. The water in the bucket stays unfrozen, it is just the nipples that freeze. What else could I do to prevent this?
change to a horizontal nipple. The seal is inside the container rather than outside so should resist freezing.
X2 what CC said. We had issues with the vertical nipples (the kind you have) and switching to the horizontal nipples has been so much better, no freezing and other benefits. If you have a bird bath heater, upgrading to a submersible aquarium heater might help, depending on how cold it gets in your area. But for less $, you can build a new bucket with horizontal nipples. You'll still want the heater in the bucket, though. Here's a good long thread comparing the two types of nipples: https://www.backyardchickens.com/t/...-vs-horizontal-spring-loaded-watering-nipples