Buy whole grains for them! They store very well if kept cool and dry.
Really you don't want to store the cracked grains longer than 4 months!!!!!!!!
It will go stale and you should see all the vitamin deficiency-sick chickens posted on in the Emergencies section. It can make your chickens very ill.
I have tried to buy the commercial feed ahead of time and it doesn't stay fresh.
Here is an idea of other things you can feed and store:
I feed wheat, millet, rolled barley, rolled oats, cracked corn (org.), BOSS, split peas and unsalted peanuts sometimes, a little kelp meal, and am going to try Austrian peas.(All mixed - 1/3 starter, 2/3 of this mix.)
Offer them grit if serving whole grains (unless you are sure they can find sharp gravel in the soil).
Edited by ChickensAreSweet - 8/5/12 at 5:44pm