I put my horse into the field at eight this morning its now half 2 she was put out with a 25litre bucket of fresh water as im monitoring her water intake. Anyway its quite warm at the moment and she has drank none of it? I am not hugely over concerned as she is actually drinking in the river when I ride and is behaving normaly. But six and a half hours is a long time to go without drinking anything don't you think? The water is from her stable water trough so she is used to it.