I'm in the middle of preparing several crops on just 5 acres total of land to feed my flock of over 60. . . I'm growing heirloom corn, quinoa, amaranth, tef, and of course whatever excess vegetables and fruit from our gardens/orchards will also go to them.
I personally am a huge fan of Amaranth and Quinoa. Very protein and mineral rich, much more natural than other grains to feed to poultry, plus the leaves are also edible, and it's pretty hardy stuff, not to mention very attractive! The key though is to buy a variety of Amaranth for flour grinding, not the leaves, and a variety of Quinoa best suited for your area. My area for example is perfect except our excess rains, which is practically an "enemy" to properly harvested Quinoa.
The nice thing about growing it is that it beats paying $4+ per pound of someone else's.
The other huge plus is that it is also very good for human consumption too, practically a super-grain, and used often in gluten-free diets or as a good cereal grain. I'll be growing mine for both the flock and my family.
Another thing of mention is corn. . . Pretty good stuff, but especially finding a non-GMO, heirloom variety best suited for your area is just the best! Out here in the Pacific Northwest, growing corn is near impossible, however there are some really neat varieties that have short growing seasons suitable for out here. Best part about them is their amazing colors, such as green, blue/red, or blue/purple/pink/white.
Oh, and of course, planting legumes such as beans amongst your corn not only supplies the extra nitrogen it needs, but also more food for you and your flock.
