If you don't feel like reading, skip to the bolded part at the end. I didn't really need to write this whole thing, but oh well. It's done.
Here's the situation:
I have a gelding and a mare. They LOVE each other.
They used to be really herd-bound at my last barn. They had been in adjacent stalls, and were turned out together every day. We switched them so that they were one stall apart, and turned them out separately every other day (and turned them out together every other day). A couple weeks of this and they were no longer herd-bound at all.
So... I switched to another barn and they were perfect the whole time I was there. Then I switched to another barn and they went back to being herd-bound. When I take the mare away, the gelding freaks, but the mare behaves perfectly. When I take the gelding away, he gets a little upset, but behaves. The mare is fine.
Well, when I say he freaks when I take her away... I really mean it. He tries to kick down his stall. I have to put him on the walker when I take her away so he doesn't do any more damage.
I'm going to do what I did before to separate them for three reasons:
1. I'm going to take my mare away for three days for a trail ride.
2. My gelding is now prone to ulcers and colicking from the ulcers.
3. I'm putting my mare in training, and it will be easier on the trainer if he doesn't have to put the gelding on the walker every time he works my mare.
We're going to put a horse in the stall between the mare and the gelding. We're going to put the mare in a pasture with other horses. We're going to put the gelding in the pasture that he used to share with my mare. They had this pasture to themselves, so that means he'll be there alone from approximately 6pm to 8am. I can't turn him out with other mares because he breeds them. I can't turn him out with geldings or stallions because he attacks them. I really don't want him to be alone all night long. Does anyone have a solution?