This is an interesting thread of thought. Something that i am constantly researching. I have fed dumor, blue seal, purina and now nutrena. I really like that manna pro has realized that some folks don't appreciate the soy content in their animals feed. They have a layer pellet that contains fish meal, but a small bag is $17.99. There is corn as the first ingredient however i think of corn as a binder grain because when ground it makes a paste.
When i took over Chris Kings silver flock, i changed the feed i was buying to nutrena, however i had already been supplementing once a week over feed with a product called "Power Punch". I noticed right away an increase in laying and vitality in the birds. A little goes a long ways.
I feel like most of the great nutrients our birds need are cooked out of the feed.
There is also a calcium drench i have on hand. It is slso packed full of those essential vitamins and minerals. (I have milk goats on our farm)
I think from this standpoint, humans are given a prenatal vitamin, so are other animals. I have had 3 excellent hatches over the past week. I am certain the vitamins have something to do with that.