I have been feeding my horses with slow feed hay bags for the past couple of years. I have noticed such a difference in not only them not wasting hay, but also in their manners as it keeps the busier for longer. The only issue as they can be a little harder to fill, and I also hang them up so that horses cannot get caught in the bag in any way as I don't want them to get hurt. I have owned this specific hay bag for about 6 months now and this one compares well to all the others I own also, but is at a much better price.
i use these with miniature horses, who tend to get overweight easy. I have several bags. Great healthy way to feed, clean, cuts waste to almost nothing. They are satisfied with less and cuts down on boredom when stalled.