I just follow momma hen's lead. She gives them little bits of grass, bugs and seeds. In the process they also get plenty of dirt. So when I raise some whitout a momma, I go out and get little clumps of nice grass, so they can tug on it and the roots and they can peck at the dirt. I cut up bits of grass into small pieces just like the momma would. If I come across little worms or grubs, I give those to my chicks also. I will also give them a few bits of cooked rice. Not too much though, since I don't think it has much nutritional value. I also give them sprays of millet that we grow ourselves. Sure keeps them busy. Again, I don't try to overdo it, this time because millet is high in fat and I don't want them to fill up on just millet. But they play with it a lot too. I think as long as they eat mostly chick starter, they ought to be ok.
When the chicks are with a momma hen, they eat very little chick starter, coz the momma takes them all over the field. They end up good and healty little chicks as well.