I have a 5 year old labrador from working stock. He is sooooo different from any other dog I have had. He loves to chase rabbits, squirrels and deers. He gets a scent and then is it total deafness to us and his otherwise brilliant recall. He can go off for 15 mins at a time but is always able to track back to us. But that is not the point I worry constantly when out walking him. Is the only option to keep him on a lead?