Most pastured layer folks who do it at modest to large scale and use whole grains offer fish meal too. Here is a typical one:
Justin Rhodes Chicken Layer Grain-Based Recipe
3 parts Corn, 22.5
3 parts Wheat, 40.5
2 parts Peas, 47.8 [at 23.9% ea est]
1 part Oats, 11
1 part Fish meal – 60%...