Something to try, when you throw into cover with your scented tennis ball or wing preplant the area your throwing into with pups favorite treat. Plant three or four of these in different locations before you start and hopefully the association will be made. A friend of mine did this with his female rottweiler and that dog would topple a stand of russian olive but you'd have a quail, hun, or pheasant to show for it. Good luck and good hunting.