I have hatched out many batches of chicks, and have used the smallest chicks of one batch to help raise the next batch of chicks maybe one or two weeks apart. It helps a small chick not get run over by faster growing chicks, and the new chicks get a chance to learn the ropes of eating and drinking water. The other thing I like about it, is a small chick that may get over looked in one flock becomes a hero in a different flock.
Here is a pic of my latest chicks held back with my new chicks.
Here is a pic of my latest chicks held back with my new chicks.