I had 107 chickens before we started thinning the flock. About a 5th of those were small chicks, some older chicks, can't remember exactly, but a few weeks old anyway. I had 53 layers and 3 mature roosters. I free range them on a good pasture (alfalfa and grass) and fed them ± 14lbs of food per day. I only fed cracked corn though, as my chickens have access to greens and there was no difference in egg production when I did feed layer pellets.
If you feed them outside make sure wild birds don't eat the chicken's food. They can easily eat as much as the chickens! I scatter the food and stand by them until most of the food's gone, otherwise I feed the entire neighbourhood's birdies.