There is one lady on BYC who feeds lentils uncooked. I have read that it is fine but that the tannin content is a bit higher than with the peas, is all. You should be OK in moderation.
Azure standard sells that Scratch and Peck soy and corn free mix but I haven't tried it. I prefer some soy...
Oh I forgot to mention that I like the Redmond mineral conditioner also from azure (I leave it out free choice for them) and make sure to give them greens year round (like alfalfa cubes that are soaked) or green grass year round (chopped alfalfa hay in very short lengths also, for example) for...
Don't forget about split peas, going for about 50 cents a pound here and 24.5% protein. They don't need to be cooked for poultry. Lentils have more anti-nutrients in them than split peas (tannins) and thus I'd limit them personally. They will eat the split peas if mixed into the feed and not too...
Corn and soy are fine (non-GMO) in my opinion but they would be healthier with a little added variety- at the very least some greens like grass or free ranging to eat weeds/grasses for vitamins.
I buy organic soy/corn feed (the only ingredients in it are soy and corn with artificial vitamins +...