Currently, GMO corn is only in animal feed. But the problem is that you cannot simply go to the elevator and request "GMO Free" corn. Feed corn is feed corn, whether it's GMO or not. That was the big coup that Monsanto pulled off a few years back. It took a lot of lobbying, I'm sure.
I raise "all natural" free-range chickens and sell them to friends and neighbors. I wish that I could get corn that was GMO-free, but the only way is to purchase "organic" (TM) corn, at about 10 times the price. At that point, I'd have to sell the chickens for $5/lb and no one in their right mind would pay for it.
Monsanto knew that if their corn had to be silo'd separately from other varieties, that it would be worth a lot less, so they had to get it commoditized with the rest, or all of that R&D would have been wasted. Good for them. Bad for us.