If they don't sell heated waterers - What about one of these? http://www.amazon.com/s/qid=1230223577/ref=a9_sc_1/186-2143973-7898145?ie=UTF8&search-alias=aps&field-keywords=mug%20warmer
I use a large glass measuring cup (the pyrex kind with a pouring spout) in the winter for my girls and I've...