We recently ordered a feeding net from Cinchchix.com. It's a net bag that opens and closes on one end. The net mesh is small enough that a horse can't get it's hoof stuck in the netting.
You put the net bag over a bale of hay, close the end, and let the horses work on it. Our six horses used to wolf a bale of hay in about an hour, maybe a little more. I was feeding 2 1/2 bales per day and cleaning a lot of waste hay off of the ground.
Since we started using the net bags I'm feeding 2 bales a day with virtually no waste on the ground! I put the hay (open or bagged) into feeding tubs just to help keep it contained.
It takes them all day to go through a bale now. I feed AM and PM and there has been a bit of hay left over each time--which tells me they are getting all they need and just quit eating before it's gone. I actually am using two net bags now. At each feeding one will be empty and one will have a little left in it. I leave the not quite empty one for them to finish and put a new bale in the empty one--and leave the bale tied so it's a little harder for them to start it.
Because the loose hay in the left over bag is easier to eat they finish that first. Then start working on the new bale. Next feeding, I just repeat the process.
These things seem to be working GREAT! The come in sizes for small and large bales.
One thing to note: They can't be used with shod horses! The back of the shoes can get caught in the netting and then you'll have a train wreck on your hands!
But, if you're barefoot and having problems with a lot of hay wasteage, these seem to be a great way to go!