Here is a great recipe for DIY Natural Chicken Feed. Most items can be stored long term and mixed as required.
Yields 100 lbs.
60 # yellow corn meal
15 # wheat middlings
8 # soybean meal
3.75 # fish meal
1 # bone meal
3 # dry skim milk
2.5 # alfalfa meal
.4 # Iodized salt
6.35 # powdered limestone
Mix all together and store in closed covered container.
As this is dusty add a small amount of water to what is
removed for feeding , as a binder. Do not add water to all
of it as it then will not keep as long.