I've got 66 chickens at the moment, 57 of them are mature, 47 are hens. I feed 1lb layer pellets in the morning with 3lb cracked corn. From 11:00 onwards they free range over a huge pasture with lots of greens etc. 14:00 they get another 3lb cracked corn and another 2lb at 18:00. I found if I feed them more than this the egg production drops. If I give layer pellets twice a day it doesn't make a difference, so I cut back. A farmer friend of mine used to over feed his hens and as soon as he cut back a bit they started laying more.
I'm not sure how the hens work it out, but it worked for us!