I think calling them in is hit or miss. You might scare them or it might work. We have killed two nice boars calling coyotes so it does work, and yes they make hog calls. Grunts and squellers...we called them in with rabbit distress calls.
There is a video on Youtube of a guy who calls them in I think with an electronic caller-Lots of Squealing and sounds pretty cool!..........I would love to have one..........I have a K&H Boar caller and I HATE IT.........I dont think it sounds anything like any kind of Pig.