For 39 chickens I fill a 3 qt feed scoop every 2 days. The cubes can be several inces long or centimeters. Once the scoop is filled I kinda break them up to help them rehydrate. To another person who asked about just throwing them out dry, I tried that for almost a week, throwing them out whole some of the girls scratched at them and no one had any interest (U ever see a chicken munch on dried grass?), so I thought to rehydrate them to try to get them close to fresh as I could, and they went nuts over it, scratching and clucking, and the yolks went from yellow to orange like they were never enclosed in a run.
...is it wierd that I take some of my scratch grains (or any other whole grains that I happen to have handy), line the bottom of a small cardboard box w/ them, moisten them and put them in the window sill till they sprout and just put the whole box out for my girls to eat? By the way, I only have five big girls at the moment.