It's horrible stuff, in my opinion. And it leads to people buying "chick feed" instead because it's cheaper. Then the risk is raised because many chick feeds are treated with antibiotics. But people just don't think.
I actually did try this litter during my litter experimentation stage. For one day. Queen Eva ate it and puked it up. Then ate it again. I couldn't get rid of it fast enough, and decided I didn't like the idea of using food as litter anyway.
I "try" to avoid GMO but I don't think labeling has to indicate it so it's hard to know. I did find some GMO popcorn, and OH my what a difference. One time I ran out and had to buy orville redenbackers again and it made me so sick I brought it back. I checked their website and they fall all over themselves there defending GMO foods.