Definitely salt. Here's what you do.... Go to the home improvement center and get some cheap wood stakes, the short ones. Make up a tube of strong salt water, and soak the stakes in it for a week. You'll have to weigh them down since they'll want to float. Then pound some of the stakes into the ground in the yard within shooting distance. The porkies will be attracted to the salt content and will chew on them. (I've seen them chew off axe handles to get the salt from sweat.) BANG!