You can hunt them in MI in all but a few counties as of right now any time you want to! You just have to have some kind of hunting license good at the time... any kind will doNo official season (yet) in Michigan but our feral hog population is growing. I am not sure of the count last deer season. Official DNR stance is to eliminate the "invasive species" They prefer that you have at least a small game license but if one were to be "target shooting" and one crossed the range they can drop it.
One area I hunt will be a real mess if the hogs move in. DNR will never get them out. Very remote with no vehicle access. Then again I have always been told hogs are fun to hunt. 8)