Growing Corn without Fertilizer

We produce roughly half of the calories our family eats and corn makes up a good portion of that. But, our yields are always on the low end. I swore off synthetic fertilizer and use rabbit, chicken, pig, and sheep manure. Some of it is composted, most is not. I’m sitting here wondering if it would be worth it to use vermicomposting on the manure. Would that likely be better than straight manure, or would it just be extra work? The above photo is a few of the corns from my breeding projects.