I don’t know about corn free but there are commercial feeds that are soy free now. I like Nutrena Naturewise Hearty Hen feed (also has higher protein at 18%) and a local brand Poulin Grain has a feed Egg Production Plus that is similar to the hearty hen. Maybe you could find something near you?? Not sure why you want to avoid corn but I’ve been able to avoid soy at least and it’s good feed. Though with a rooster you may not want layer feed. But there are other ones.