I've never known a horse as clever as Shasta. She knows how to open gates of all sorts and we have found her out of her stall numerous times. She figured out how to climb under her stall chain so we had to get the full, webbed stall guard. Even that can only be used under supervision as she will just break through it if given too much time. We had to add a chain above her stall door after her last escape.
She has figured out how to unscrew the grain barrels kept near her stall (thankfully they only contain hay pellets and she can't reach them without the door open).
And I don't mean flip them open, I mean unscrew them. There are teeth marks all over the lids. Here's a close-up:
She will turn the lids with her teeth until loose, throw the lid off, and stuff her head in. She wasn't able to open the lid this day as it was empty and thus too wobbly. But she's done it before; I just didn't get video. If she can't open it or reach the pellets once it's open, she dumps the entire thing over. That doesn't really solve anything for her, but she seems to enjoy taking her frustration out on them.
If we leave anything within her reach, she will get it. We actually had to remove her halter and lead rope from the front of her stall because she kept taking them off and throwing them on the ground.
I recently caught her trying to get some treats that were almost, but not exactly within reach.
What you can't see in the gif is that my keys are on the ground because I mistakenly put those within reach.
I've seen other horses do similar things. Reaching for a treat jar isn't that impressive. This solution to the problem though?
Genius! I wish I hadn't accidentally hit the stop button at the best moment. Sorry. She then proceeded to dump the jar over and take a treat from the ground.