Labs are great hunters and death on groundhogs, moles, voles, etc. It would be cool to let him go out there and see if he could do his thang. But then...you might want to keep the gophers as a natural prey source for predators so they will leave your chooks alone.
I think that's why folks in the 'burbs are having hawks dive bombing their chickens right in front of them, a lack of natural prey for the raptors in areas of urban sprawl, and that's why, out here in the middle of thousands of acres of forest land and possessing the only chickens for miles, I am not losing chickens to hawks and foxes. Too many squirrels and other natural game for them to feed upon.
Gust brings me field mice. Cute to see their little tails sticking out of his lips. I think they keep the hawks and the owls happy. Maybe even they keep the coyotes alive. I'm not sure what Dad's issue is with the dog being dog-like and helping on the farm. Gust seems to have pretty good instincts.