IMHO, I think it would be a waste of money. No matter how good your intentions, horses just seem to be able to take the hay and scatter it all over the place. They'd probably just yank it out of the openings and toss it all over.
What happens when the hay is below the level of the feeder windows? Does the horse have to stick it's head inside to get the rest? I can see accidents just waiting to happen with that! Can you imagine a horse getting its' head stuck inside one of those?