I was a given a good tip, Moor Mans has a 100# tub of Mineral/vitamin, supplement. My old blocks sit around and finally disintegrate, before they eat them. But they will eat, the mineral in the green tubs, even if it rains, they drink the water off and keep eating. About 1/2# a day per horse. 4 horses go thru one in a month. The foals are much bigger and stronger at birth, as well.