That is a lot of water consumption... I use two of those muck buckets for three horses, and we fill them once a day, and that's just to top them off.... they really could go two days. Does she have a salt/mineral block? Does she go through a lot of salt?
The other questions, I really don't know. I hope your vet comes out and you can ask her.
They all get minerals in their morning feed. She licks all hers out of the bucket, the others will usually leave some.
I thought she might have been drinking like that out of boredom. She was use to running in pasture you know, and now she is in a run, and only gets turned out in the little pasture behind my house a few hours a day.
Rocky will drink alot if he doesn't get turned out enough, I guess now he's just going to drag the trough around:), and he's been getting out alot too. Crazy horse.
Becky