I collect bags of damp leaf mould out of hollows and ditches in the bottom of the beech woods near us, and I fill an indoor pen to about six inches deep. The hen and chicks go in there about 24 hours after hatching, and about twenty four hours after the pen is set up. The hen scratches through the mould and the chicks get a good start on live food. After that they get chick crumbs and regular top ups of leaf mould till they are about three weeks old (weather suiting) and then they go outside to free range.
My hens are very active. This method may not suit all breeds.