The doing damage or about to do damage most commonly refers to coyotes, foxes, feal hogs, etc. Either way back on topic with the original subject...if you know you have hogs on your property buy a cheap license of some sort and shoot them because unless you jump them while walking around and looking for them you will not have the opportinty to shoot one in self defense, they are much more skittish than youd think. Besides, i would think if you shoot an animal about to do damage or in self defense it will likely be like a road kill situation where you will either have to acquire a permit to keep the animal or turn it in to the DNR all together (technically at least)