After college I worked in a training stable in Ohio- had about 30 horses in stalls. Each horse had a bucket. Daily we just went along and filled the buckets with a hose. They have flat backed buckets and corner buckets. Buckets are nice, but a stock tank or pond allows you to get away for a few days without worrying about the animals and their water. The horses heat and the mild winters kept freezing from being a problem. We drained the hos every day during the winter.