By far the best "in box" feeding solution on the market. Natural eating angles, shoe, and hoof safe, easy to fill and can be pushed all the way into the corner without being damaged.
Optimal Pony takes 8kg = 20 lbs of loose dry hay or 20kg (2 complete small bales) = 45 lbs of baled hay and
Optimal Horse takes approximately twice that.
If you want the best for your stalled horse, You have just found it.