I guess I would want to know whether he was feeding them fishmeal and GMO soybeans before and just switched to the non-GMO to get the effect?
Or did he add in fishmeal and was that the confounding effect?
I would suggest sticking with Ford!
You are correct. Taken at face value, this is not a valid experiment from which to draw conclusions. "Change one variable at a time", i.e., add fishmeal to GM soybean, and/or replace GM soybean with non-GM soybean with no other changes.
When things go from science to dogma, it creates doubt in any rational examiner as to the data being presented. To me, it would seem natural that a crop which is designed to be resistant to a pesticide regimen and is heavy coated with that pesticide would naturally contain that same pesticide in some amount especially in animal feed. And it seems to be contrary to logic to feed animals an herbicide and expect no reaction from the animals.
So there appears to be multiple vectors in this study; is the genetic modification the actual difference? Supposedly it is less nutritious; that would be an issue. Did the pigs get a far lower dose of herbicides and pesticides due to the change? And how much of an effect did the extra nutrition from the fish meal change all of this?
It would seem to me that it would not be hard at all to conceive and implement actual testing of this theory. Three populations of pigs, each given a very specific feed, and see what the difference is. According to the farmer, the results of the change were dramatic once the switch was made, so it doesn't even sound like it'd be a long study.
I suspect I know what the various results would be, but would certainly welcome a surprise.