I use wheat for a cover crop in my garden and Indian corn for decoration. What wheat I harvest and don't use for seed or flour goes to the chickens. I don't grind it, I mix it with other grain for a scratch. The corn I just throw the ears in and let the chickens pick the kernels off. So how big an operation are you thinking of, farm size or backyard.
I will say that unless you know some one with a combine or thresher the work in harvesting small grains may be prohibitive, for a backyarder. I do it because I have the time. Some years when I am short of time or the wheat has fallen I will just harvest enough for seed, then just cut the rest and throw it to the chickens for them to thresh themselves instead of scratch. That way does tend to clog the run with straw though. When I had 12-14 chickens a 25'x75' patch of wheat would produce enough for about two thirds of a year mixed in a 1 part of each different grain scratch feed. Of course how long it would last would depend on how much scratch you feed.
Corn is a little different in that you can easily find corn shellers. Feeding it just on the cob is also an option. Again though you will need a fairly large section of you yard to last them a whole year.
I grew sunflowers for them. It didn't come close to filling them up, but they ate over well 100 flower heads this summer, and we had pretty flowers too.
They also get almost all the kale that comes out of the garden. I have 12 big kale plants and I bring them a big handful of leaves every day. They love it.