supplemental feed

I keep hearing about chicken owners, especially farmers who sell eggs bragging that their fully pastured chickens don't eat commercial feed but rather a specific blend of grains, sort of like custom scratch grains. The problem is that every time I try to find books about how to formulate chicken...

I currently have 31 chickens (1 rooster, 5 hens, 6 cockerels, 19 pullets), 14 guineas, and 8 ducks (1 adult drake, and one confirmed month old drake). I let them free range for at least 8 hours per day as well as give them crumble feed and I am buying somewhere between 6-7 50 lbs bags of feed...