Use a quail wing on a fishing rod and work the dog, not letting him catch the wing. Not to worry, he will outsmart you occasionally, but keep working him. As far as hard mouthing goes, take a wooden dowl & drive finishing nails thru it so points are sticking out both sides, all around. Then wrap it in quail wings. Toss it & let him retrieve it. He'll learn to have a soft mouth quickly.