It will not work to only feed them cracked corn, not balanced in any way. However-IF you had good range or pasture, once you had them well started, say, 6-12 weeks, depending on breeds, etc, you could turn them loose and feed them mostly corn and get away with it. I have done this with rock cockerels with reasonable results, yes, slower growth and smaller at slaughter weight, but, very very little money and time invested. I'm am not sure this would work with cornish cross, though. Be sure you have good forage available, and this could work. Would work really nicely for geese!!