So I did this water test a few years ago, and now this winter.
My horses have two insulated buckets each, except the minis who have one. I also have electric heated buckets that I have not used in years. I now remember why.
I set up the buckets and gave my horses the choice of insulated vs. heated. They chose to break the skim ice out of the insulated buckets vs. even touching the heated. Except the minis, who are weird anyways.
I do have the heated in the stalls until this cold passes, but I will take them out after and either store or sell them. Must remind myself in a few years they don’t like them. At least I got new extension cords for the fans in the summer!
) who don’t like heated but also want warm and will make a hell of a mess and throw withering looks at any passersby if the water is not up to par. Spoilt. Yes, it’s my fault. No wait! It’s a previous barn owner’s fault for always topping up with hot in the winter. And, um, yeah, ok, a little bit my fault because I kept up the practice when I started doing night check for her and then kept it up again when I moved to a self-care facility. 
