I strongly suggest you not do this. For most people, in most situations, its not cost effective, its not time effective, and it introduces significant (and unnecesary)uncertainty into your chicken's nutritional intake.
If you choose to "bend the curve" on feed costs by devoting some of your grounds to edibles for your chickens, the first question to ask yourself is "what grows well where I am". The second question is "are their any soil deficiencies I should be aware of". The third question is, of the things I can grow, given the limits of my soil, which crops have the best cost/benefit ratio for me???
Example. SE Washington (State) produces a substnatial amount of wheat. Its also selenium deficient soil, which makes selenium deficient wheat, which makes seleium deficient chicken feed. But having decided that thereis no better crop to grow in that area (because wheat is more nutritionally valuable than corn as a chicken feed across most metrics) one can choose between "soft" wheat varietals and "hard" wheat varietals. Hard wheat has higher crude protein per unit of measure, and is the superior choice.
Maybe your climate and soils are only well suited for peas? Choose yellow peas if you can, not green. Lower tannins (an antinutritional factor present in all peas) in the yellow, and likely to be more palatable as well.
Now, knowing what you want to grow, start researching companion crops to restore the soil and support your main crop - chances are, your birds will benefit from those too.
and FWIW, I have a pasture, my birds free range it daily w/ 24/7 access. I've chosen to load it with four kinds of clover. Several grasses. We have sorrel (in small amounts), some flax, and every year I try to introduce other plants to see what will produce and self sustain - I've tried millets, buckwheat, sorghum, sorghum/sudangrass hybrid, perrenial rye, deer corn, chufa, radishes (several varieties), amaranth, puple hyacinth bean, methi, oregano, others. Based on how things are doing in the pasture, I can reduce my bird's feed, sometimes significantly - but I won't pretend I could replace it with the output of my pasture, nor could I successfully store it for my few months when little grows.