I make up a mix of black sunflower seeds ( for brilliant shine on black coats ) steam rolled oats (keeps weight on poor doers) cracked corn (makes yolks extra gold) milo or sorghum (for variety) and soyabean meal ( fantastic protein source and they love it, I have the glossiest coats I’ve seen on any birds ) I chose these grains as I used to show horses and cattle ( with always the best results ) and the chickens were always looking fantastic and only ever died from old age. Now I’m in the suburbs and still getting comments on the brilliant shine even from people who have never showed an interest in chickens. They still free range around the garden during the day so always have access to greens and I also encourage vegetable scraps and fruit daily.