I wait till there fully mature say 12months before lamping them I like to get them pinning to nets as young as possible to build confidence. Dropping rabbits to a young dog teaches them nothing bar putting pressure on all muscle An joints that are not fully formed plus you could potentially be setting your pup up for failure with a dog that’s not mentally ready in turn createing a yapper or if your in to much a rush without putting the time in with retrieve work it’ll all go out the window on a unmentaly ready pup