I live in a small village in Mexico. Our chickens are Heinz 57. I'd like to come up with a simple mix to supplement their browsing The choice of prepared food available here seems to be whole corn, crushed corn, and a mix for fighting roosters. Our chicken are free range and this is the tropics so they get lots of bugs and plant life. I've looked at a lot of the diy formulas for feed and most of the ingredients aren't readily available. I'd appreciate any help. thank you.