When you don't have a lot of money and there isn't a lot of acreage, it can be a mighty big blessing to be able to think outside of "the box". We have had an ongoing problem between Max and Shadow; Max absolutely loves irritating the stew out of Shadow, especially at mealtimes (see first photo - taken with my cell phone, sorry).
We had hoped that when we began building the barn by creating some [outdoor] stalls, the temporary round pen panel between them would be enough of a deterrent. It wasn't. Then my husband put a 4x8 sheet of plywood between our two problem children to no avail. Max continued to needle Shadow from his side of the wall until Shadow finally knocked a hole in it. This created a bigger problem: Shadow is constantly shifting when he eats. While he generally started out each meal with his rump pointed at the door, he would often shift off to one side or another as he ate. Max eventually figured out that if he was quick enough and timed it just right, he could dash into Shadow's stall without getting kicked and steal the rest of his feed. Shadow would bite Max in the head, ears, neck and everywhere else he could reach, but once Max got his head in that bucket it didn't come back out until there was nothing left no matter what Shadow did.
Now we probably could have locked Shadow in his stall, but he tends to stress over that (and locking Max's would have just made him work harder to annoy Shadow while he ate). So what did we do? We simply moved Shadow's bucket to the opposite side of his stall right next to his door. Coming eyeball to eyeball with Shadow was enough to deter Max from trying to sneak in (he couldn't). Yes it's a bit annoying having to climb through the slats into Shadow's room to dump his feed, but the blessed peace that has been created by employing this strategy makes it completely worth my while.
Of course Max was then obligated to revise his scheme and swap to Plan B: pushing his nose through the slats over the bucket and haranguing Shadow until he bites Max in the head (almost always with a mouthful of feed). This causes some of the feed to dribble out over Max's head and onto the ground.
So now Shadow is happy because he got to bite Max and "make him" move his head, and Max is happy because he managed to dupe Shadow out of some feed.
Yep, it's a win-win situation all around :o)