There is a "breeder ration" that you MAY be able to find locally. It is impossible where I am. What I do is suppliment. I give layer crumbles (3lbs per 10 birds (standards)) and suppliment with protein, vitamins, and iron. You can buy protien tablets to add to water once a week... same with vitamins (A, D, E for fertility)... and I give spinach and deeply colored green greens for iron.
If you can find breeder ration though... it's all you need. Also, too much scratch can slow down laying... and eggs are money if you are breeding. Should only give what they can eat in 5 minutes. It's a treat, not a staple. (I use it as a lure to get them back in the run from "free range" time lol)