GMO is perfectly safe to eat.
But it is the environmetnal issues like Round Up resistant crops that is concerning.
As for corn, my birds are eating their normal amount of layer crumbles but also topping up with a lot of cracked corn for calories. The last month we've been down to -30C and rarely morethan -10C. They need the extra calories to stay warm. There has been no drop in egg production.
I know this is an old post but just wanted to say that we know better now. GMO is NOT perfectly safe to eat....... Check out this info:
http://www.naturalnews.com/037249_GMO_study_cancer_tumors_organ_damage.html