I don't agree with shooting an innocent dog. That dog doesn't know that she shouldn't be on your property. The owner needs to be held responsible. I would give him a piece of my mind.
That dog is not doing anything any other dog wouldn't do if it was loose. Shooting a dog isn't going to solve anything. The pups probably won't cause you as much problem if you think. Any real hunter that is going to hunt hard enough to catch many hogs won't be buying pups from unproven crosses with an unproven dam and an unknown sire.