Well yes... but then the aquarium heaters probably try to heat the water to 70, instead of 40 like a de-icer.I put my aquarium heaters in 5 gallon buckets with the lid on, and plug them into thermal cubes so they only come on when it's cold out.
However, in a nipple waterer, you probably need the water heated up to 70-ish, or the water would freeze in the nipples.