I mix my own scratch and then ferment it with kefir as my starter. I feed this as the primary ration to my flock. They free range all day and that foraging seems to cover any deficiencies in my ration if there are any. My chickens do really well this way and it is cheaper. I buy a totes of wheat cleanings(mostly wheat with some weed seeds and chaff) as the base and add other bulk and bagged grains such as milo, oats, corn, sunflowers. This year my friend grew some organic non-gmo soybeans. So I bought a tote of those. You have to roast them first but thats not hard. I do a barrell worth at a time. My orchard pigs get the same fermented scratch mix to supplement the grass in the orchard.
Works well for me and saves money. More importantly my animals thrive on it. The foraging is an important aspect of my way though. That covers the micronutrients and such.