try those pads you heat in the microwave. I heat one and put it under a quart waterer on a solid concrete block and the water will stay thawed all day below freezing. We have only really been in the teens this year, but if I can put it under the water at 5 in the morning and come home at 9 P.M. it should work for those with better hours.My heated watering dishes with heat lamps aimed on them...froze...:/