When working on the farm we set water stations up in the field. We dug about a 6 foot deep hole below the stations and it left enough warm air up to keep the water thawed most of the time. Wonder about setting a hive over a hole like that?
We do the same thing at work for the horse's water bowls in the field, 6-7 foot deep hole with a 12" wide pipe in it, to draw warm air out of the ground in the winter keeps the under ground pipes from freezing as they come up out of the ground into the bowls . I too was thinking of it for hives but came to the conclusion I'm too lazy to dig a hole that deep.