Have you hogdoggers noticed the pigs actually getting larger on average over the years? - might indicate a natural adaptation.
Also, i didnt know they were a problem in Michigan already - with their winters, probably Russian blooded varmints. Matter of time before they spread out over the Midwest. Snake-head fish in the waters, asian long-horned beetles in the trees, pigs in the woods - WHAT do we pay these govt. agencies to manage invasive species ANYWAYS!!!!