Cheers everyone
Sorel I showed him what quarry was at about 7 months just so that he knew but then held him back until he was probably ten months and introduced him gently. Ten month might sound early but I knew the dog was physically ready to start having a couple of chases. His prey drive has kicked in properly now and he no longer acts like a pup, he will in the park or garden when you have a ball though . Only you will know when your dog is ready, don't overmatch him though, i keep mine away from big rabbits for the time being.
Cheers, Gnipper