My husband brought home a truck load a couple years ago from a bed replenishment project, dumped it out on a tarp and after an hour bashing with the sledge hammer he took a break. The pile is still there. My ladies enjoy digging through what is now a well worked pile of shells and soil. So, I bought two 40lb bags. My silkies like tiny flakes and powder, my layers like the smaller than a pencil erraser flakes and my duck hens just shovel down what's left.