Time and practice. I have dogs that just don't get rabbit fever until they are ready. What I do with these dogs is pretty simple. I stake all the dogs out on a tie-out inside a rabbit pen. I let my jump dog and my check dog of lead and turn them into the woods. I keep the pups on the tie-out until they are ready to explode from whatching the other dogs work. THE SECOND I see them goofing off, playing with sticks, and distracting my Varsity Squad, I put them back on the tie-out. When we get home, we play. The dogs learn very quickly when it's play time and when it is "go time". Don't worry. Put a caged rabbit in front of him and turn it loose. All that needs to happen is for the dog to catch the bug!