You can find directions here on raising meal worms--that would be easy and highly nutritious. You can also feed them vegetable garden scraps and kitchen scraps. I would keep corn to a minimum though, as it is so low in protein and other nutrients. Can you range them on grass? Be creative, and I am sure you can find ways to keep their food costs to a minimum. Call around and see if you can get a better price on their feed somewhere else...There is a wide range in this area.