I would think we are probably at the bottom of the power range. I shot a 250# feral pig that had no appreciable shield with my 43# bow and a 500 grain arrow with a good, sharp 2-blade broadhead. The first arrow went through the lungs, but stopped in the far-side hide. The second arrow penetrated up to the fletching, with half the arrow hanging out on the far side and really opened up the heart. I THINK there would have been sufficient penetration even through a shield, but it would probably have been close and definitely would not have exited.
Pat B is probably the one who should be answering this - he slays pigs seems like every week.