Used to hunt hogs with a crossbow. Do what Halfbaked and The Rev said.

I would just add, a little lower than a deer. If you go to high, you will be in the shield. Thats not really that big of an issue with a compound, but does make a difference with a longbow or recurve. I shoot them all the time with longbows (my land is eat up with them ) and like to put it low and behind the shoulder. And as mentioned, my favorite is a quarter away. Slip it right in behind the ribs and into both lungs. With younger hogs and sows, there is less of an issue than the older boars. The older boars will fight and build up their shields pretty thick. Even with that said, I have never had a sheild stop an arrow from any compound bow. And Ive taken my share of 250 + lb hogs and a few above 300+ lbs.