We have one horse actually that has to eat grass hay in small square bales. He has COPD.
Those small, square bales are hard to get by the way. The big round bales have mold and dust and stuff. So the vet says we should feed the small ones if possible.
So I hunted on the Internet for square hay bale feeder and found this place: http://www.squarebalehayfeeder.com/
I sent this image to a friend of mine and his reply was "That looks pretty good lol. If I was a horse. I would use it." Made me LOL.
Well, I guess it is too early to know yet if the horse is going to like the thing.
The purpose is to keep the hay off the ground and to not waste anymore than necessary. That's our purpose. The horse may not see it exactly the same way.