It's amazing how many owners who let their dogs roam, have no idea what they get up to. Many moons ago I had a German Shepherd who was pretty keen on hunting. One day I got into a converstion with a German chap & explained to him about my dog & that GSD's arn't supposed to have strong hunting intincts & he said to me " Any dog will hunt if it has the opportunity".......wise words indeed which have remained with me since.
Ironicly the one dog I ever had with absolutely NO prey drive was a wolf/malamute cross. That said, I'm sure she was a one off in that respect.