There are three aspects to organic feed: one is that the crops were grown without pesticides and without artificial fertilizers. This reduces toxin intake of pesticides.
Artificial fertilizers block vitamin A - a chicken researcher veternarian from a university in Colorado from the forties told me (he's now our local vet) when artificial fertilizers were introduced, all of a sudden livestock began getting sick. He and others at the university researched it and discovered artificial fertilizers blocked carotene in the plants from being turned into Vit a in the animals. They researched a remedy and started supplementing the animals with cod liver oil to fix the vit a deficiency, and vit A supplementation in the animal feed.
The third aspect is that organic feed must not contain genetically modified grains or beans. Corn and soy and cottonseed are three. Wheat and rice are in the growing out
phase. I too didn't pay extra for organic feed when the issue was pesticides and fertilizers because the farmers only have to give their word it is. And I know they won't
watch an entire crop die w/o trying to save it. But I do now do everything to avoid gmo food.
Link about the hogs going sterile on gmo corn:
http://www.naturalpedia.com/GM_corn.html
Currently, thousands of farmers in India are having tremendous difficulties with gmo crops. A common practice for centuries is to turn livestock out in harvested fields
so the animals can eat whats left of the crops. Turned out in gmo cotton fields, the animals die in a short time. This has never happened with traditional seed. The
organic cotton also causes terrible contact allergies in the pickers.