there is absolutely nothing in layers pellets that you can't provide for your birds with other foods. Layers pellets are just a convenient all in type of feed really . The feed suppliers will tell you that you NEED to use their pellets for best performance etc , but if you were to give your birds a varied diet made up of grains and veg and allowed them free range , they would be getting everything you get in layers pellets , without the chemicals etc that are usually dumped in ready made feed.
You can use a rough guide of 1 square yard of grain sown , wheat , barley , oats or rye , will give you approx 1/2 - 1 lb of grain at harvest . So if you need 56 lb of grain , sow 56+ sq yds of grain . If you are going to try to grow any grains such as wheat , barley , oats or rye now , you would have to make sure they are spring sown types now . If they were winter sown types, then they most likely wouldn't head up , ie they wouldn't make any seed heads . So all you would get is long grass !!! Winter sown types need the winter weather , frosts etc, to stimulate them into forming the seed. Plus some need the much longer time period as well.
Spring sown grain will harvest in a much shorter period, but you may not get such a big crop at harvest .
Maize/sweet corn is different , and some people have difficulty growing it , but you can do it if you want it , just sow in as large a block as possible . You can also grow comfrey to cut and feed to your birds , (this is high in protein 20-22%) , plus any waste veg .
All of this depends on how much space you have and how much work you want to put into growing food for your birds/livestock.
But by growing your own feed , YOU are in control of what your stock eats , and therefor what YOU eat .
Hope that helps in some way ...
cheers
Russ