Bee, GMO is not my biggest concern right now. My biggest concerns with GMOs are pesticide use (will show up almost no matter what hay I use) and environmental concerns... Not so much the impact on the animals.
Like I said, I suspect the issue came from the containers, not the alfalfa itself. Grow frames aren't happening in the winter up here. We just got a foot of snow in 24 hours. My yard doesn't have grass let alone my chicken pen! It's all mud underneath, too. My site has horrible drainage too and while I am working on it it's tough. Most days my yard is a lake.
By summer I intend to have a fodder system going on. I think that will do wonders. But I am still looking for alternatives to a feed-store based diet for my own personal sustainability. If I can work out how to balance my hens diet on mostly fermented hays and sprouted fodder I will be quite pleased and may be able to switch my egg layers to an "organic" diet eventually with little impact on my budget and the added benefit of being much more sustainable.
I got ya on the GMO thing...it's an unavoidable thing here now and so I don't worry my brain about it. I'm hoping the FF will negate most of the harmful aspects of the GMO grains and then leave the rest up to the Lord. It's not my concern at that point.
