How to get range on a dog?

Patience is a virtue...especially when starting the young ones. If you'll do just as you described by ignoring them, the ones with the natural hunting drive you're looking for will eventually get gone. Once they figure out there are hogs to find, they will be blowing out of the box to get gone.

I use the same method when evaluating my litters of pups. I'll even load the litters up and go dump them on a place where there aren't hogs. My main objective is to sit (however long it may take) and see which ones eventually will get gone. Multiple times of doing this will typically affirm the results...as it's usually the same ones over and over that are catching my eye.