Ok so I took my Lab to a kennel to be obedience trained and to retrieve dove. I never hunted ducks until last week and now I'm hooked. I wanted to start training my Lab to retrieve duck. Since he's already obedience and has some hunting experience I think I could do it myself. I know that its more difficult to retrieve ducks so I wanted to get some recommendations on what books or DVDs to get? I'm wanting to do the whistle and hand direction for blind retrieves.