Common sense mate.When you know a pup wants to chase and catch and can run and turn quick enough to catch a rabbit then the time may be right to take it out. Take it out on the lamp when the conditions are right ie dark,windy night and to a place where the grass is not too short etc. The best dogs I've ever had have all caught a rabbit by the the time they're 7-9 months. I like to take a pup along when lamping with a seasoned dog. The pup will know the score soon enough and when it's standing on it's back legs pulling like a c--t when the adult dog is slipped you will know the time is right.Good luck.