Layer food is convenient and has mostly what a laying hen needs. That does not mean it is the only way to feed. There are members of BYC where winter is not harsh that have successfully allowed flocks to free range without supplements year round. Others such as Tipharah who use an alternative way to provide the birds what they need. I do not know the exact nutritional needs of my birds as I use the easy way of commercial feed, oyster shells and free range. The information is out there, and I am sure known by other members of BYC if you would like to continue your research and feed a diet that does not involve commercial feed.