I've made my own, with slightly bigger holes for the oat hay, a couple of hours work and some baling twine, and am now at 2" standard holes, since they mastered the oat hay
My hay bill is down dramatically, horses are never out of hay and consequently never hungry.
They used to have about 30lbs each a day, nearly 10 lbs each ended up inedible, now maybe a pound, max 2 is on the ground, but not trampled and they together eat 20-25 lbs. Together, not each!. I keep my nets full, but weighed everything daily for about a month, and that is what they consume. Most amazing!