I had this problem when the automatic waterer was
touching the electric fence and shocking the goats. Once I fixed the fence they
still were leary of that tank. So I did as someone else also suggested. But
first I gave them minerals and salt to MAKE THEM REALLY THIRSTY and then took a
bucket of water that I knew they would drink from let them drink from it by the
tank and then put the bucket IN the tank a little at a time until
the bucket was under the water while they were still drinking. It did work. My
stock tank does have a heater in it. I use a rubbermaid and have the heater that
goes in the spicot so it's on all the time. I also took pvc pipe to cover the
cord so the critters couldn't chew on it. It has never shorted and I've never
had a problem with it. I even dump snow in the tank to melt for
water.