Easiest way to find out if there are pigs around is soured corn and a game cam.
Put out regular corn and the deer may/will get it before the hogs find it...
If you dont have time to sour corn get you a small spray bottle of diesel fuel and mist the corn enough to make it smell.. Deer wont eat it but the hogs will. I keep a old 2 oz doe scent spray bottle with diesel in it in a ziploc bag.
Here is a picture of what rooting looks like...... Ive never seen them tear a entire field up...... just spots like in this picture