If it were me I would stop hunting him for a bit. Sounds like he needs to mature mentally. I would get some pigeons and let him chase,chase,chase build his desire for the bird. Then I would take some pigeons tie about 50 -75 ft cord with something heavy tied to it. Throw up the birds just before he hit the end of the string I would have some one stand way off and shoot just before the bird falls. then release dog to fetch it. He needs to learn to associate the gun fire with the bird. Just my thoughts. I still do not under stand why people need to have a 8 -9 month old dog hunting.....You would not expect a 3 year old kid to hunt?