I feed a 16% organic grower feed providing calcium in the form of oyster shell in separate containers for those actively laying.
The feed is a complete ration, as are almost any chicken feeds you can buy.
If I'm feeding chicks, I add fishmeal at a ratio of 1:10 to raise the protein to 20%.
I do feed table scraps but with anywhere from 30-100 chickens, each one is lucky to get a bite.
I also give some animal protein in the form of grilled raccoon/trapped predators or grilled meat that is past it's best by date.
They forage as well but half the year it provides very little but entertainment. In the dead of winter I sprout or grow short fodder from wheat, barley, peas or buckwheat but that still makes up less than 5-10% of the diet.