With the bow, take a quartering away shot, to get behind the "battle plate".
Shotgun- Slugs or buckshot ?
Tip- TAKE AS MANY AS YOU CAN ! ! !

Kill them all... just kidding in Texas we have them coming out our ears and they really do alot of damage. I would use slugs, as buckshot really cant be trusted at further that 35 yards on a big boar. have a blast and enjoy the BBQ

Do not use "MECHANICAL BROAD HEADS PERIOD!"

Didn't know they were in Michigan... if they are like our feral hogs in Georgia, they are very dangerous when wounded so be careful with the bow... it is best to be up off the ground. If you can bait, dig a 2 foot deep hole, 6" in diameter and fill it with soured corn (soaked in water and a can of beer for a week before use). It takes them about a week to dig it out and they keep coming back. You can also hunt them by stalking... Use the 12 gauge with slugs... walk very slowly into the wind (they have a better sense of smell than deer) and poke into thick bedding areas along swampy or water areas. They like to bed near water and mud. They will often give you a shot when you jump them. Good luck! Also, I might add, hunt with a buddy to back you up and consider them dangerous game. Make your first shot count. Check this out http://forum.gon.com/showthread.php?t=415156 I have come real close to having one of these myself on a couple of occassions.