Edible Acres shows a way of doing something similar but without compost: just have a few wire rings in which you scatter some seeds or grains and let the chickens enjoy the sprouts a week or so later. If you start one every day, you can keep it going for the whole growing season.

I was doing that and now am moving them between two compost piles (which they LOVE!), and want to add back the rings so that they have both.