I have 2 types of slow feeders. I have the home-made box with a wire gate on top that fits 3 squares on their sides (I leave the wire on). I also have the CinchChix slow feed net for round bales. I love them both.
It cuts waste significantly. I have 2 rounds with 10 geldings and it lasted 6 days longer with the nets than without for a total of 14 days. The box type will only accommodate 2 horses at a time.. 3 if they are especially buddy buddy.
Hard Keepers - Slow feeders are IDEAL for hard keepers because the smaller amounts over a longer period of time increase digestion and absorption.
I also have horses missing teeth and they make it work too.
WARNINGS- No shoes with nets. There is a learning curve and they will be pissy ponies for a couple days if sharing with a group. It WILL eventually help calm things down by keeping them busy but it will cause fights a first
You can check out the pictures of my slow feeders on my facebook wall photos. www.facebook.com/starlinestables