I try to feed my birds more organic. While the organic feed is much more expensive than the feed I use currently. I checked my local store and find them have cracked corn and soy bean meal. The cracked corn is cheap. While the soy bean is only $2 higher for 50lb than the feed I am using. While now, I have some concens about changing the feed: 1. How often I need to add oyster shell for the laying hens? Do the meat bird need oyster shell also? 2. What is the ratio between corn and beans? 3. Should I add Vitamines to them also? 4. Any other choices to make the organic feed as cheaper as the commecial feed. (my local stores only sell "blue seal". The feed is around $15/50lb. Thank you.