Our live lamb crop this year was 206% out of our ewes and 147% out of ewe lambs.  All our corn is GMO and this is the best year we have ever had.  Once the lambs are on creep feed, they get GMO corn and pellets made from soybeans.  Can't prove one way or the other what the beans are, but I'm pretty sure they come from GMO beans.

I didn't feed any corn to my cows this year, but have in the past with no problems.

I'd say GMO has nothing to do with anything.  It's all management.