I also throw 1 cup of scratch around the run when I let them out in the morning. They have access to their crumbles 24/7, as well as grit and oyster shell. I run a home day care, so the girls also get a "lunch" from the leftovers as appropriate - they love mac n cheese, fish sticks, corn, carrots, etc. I figure if it's good enough for the children to eat, the chickens should do fine too! The chickens also get garden leftovers
