I have a 5 year old gelding that normally does not drink much water. When I check the tank daily, his is usually only down a tiny bit. He has been very healthy and I never worried about it. But recently, the last few days, I've noticed that he takes BIG drinks, leaves the water tank, then returns within minutes and drinks more. The weather can't be the problem because it is raining almost every evening and the days are very comfortable. Could this be a symptom of something wrong or am I just paranoid. Any ideas? Thanks.