D,
Invite my husband over to go elk hunting!

It is so hard to get drawn for an elk tag here. (Just kidding sort of,

Please no one get mad).
Is there a way that you can put the horses in stalls to feed them? Unfortunately we don't have that problem here.
The only other thing I could think of is feed them some cheap or old hay on the other side of the fence, maybe that would keep them from jumping over and eating the horses feed. I know that's just what you wanted another feed bill.
Can you call game and fish and see if they could help you or give you suggestions.
Hope you can get it figured out,
But if not we love to have some elk meat. (I'm so bad sometimes

)