I recently saw a TV show out of Nashville TN that discussed wild hogs. The information on the show said that 90% of the hog population needed to be harvested every year just to keep the population stable. They compared that to deer, which only needed 30% of the population harvested to keep the population stable. If I remember correctly Tennessee recently closed the hunting season on wild hogs; since they maintain that studies show that a hunting season causes the rapid spread of wild hogs due to hunters wanting some closer to their home to hunt. They buy or catch some and release them to hunt closer to themselves. The state instead passed laws allowing the landowner to kill them at any time and anyone that the landowner gave written permission, I think, to do the same. They thought by going this route they could slow the rate of spread of wild hogs.