There is a website I found once that helps put hunters in touch with farmers to hunt their land. I'll dig around and see if I can find it again. You can ask farmers in that county if they have seen any hogs.
The county you want to hunt might have a conservation district. Someone there might be able to put you in touch who know were the hogs are.
And one last thing you might try is contact Eric Sharp who writes for the Detriot Free Press. He recenty wrote an artical about feral hogs in Michigan.
http://www.freep.com/article/2011020...doors-tip-week
He might have some info to help locate feral hogs.
Good luck!