Good time to be 7 months, by the time the season starts, he'll be the perfect age. When he's 9 month mate and your out on your walk, let him chase the odd 3/4 grown rabbit but try and make sure the odds are in the favour of the dog. Letting a dog watch a rabbit run away on the lead can have a negative affect so, its just all a learning curve. You just don't want him to be chasing lost causes without any outcome, thats a sure way of encouraging him to yap.
a person of many words? do your own thing mate your dog