To protect property from them, right? Pretty sure it doesn't have to be your property.
Doesn't have to be, but if the property belongs to someone else you have to be acting as the agent of that landowner.
You still need a license to kill hogs on your own property, unless they are causing damage.If you have the land owners permission its the same thing as being your own land... But double check that one with a game warden... But on the sensible side, SHOOT EM ALL!!!!