I had similar problem's Sock's with a fooking hare..i was of out with the pup around the 7mth old mark..if i knew it was going to be there i would of avoided it like the plague..she found it and screamed her lung's out chasing it but thank the lord she lost it in thick cover sharpish and she has kept quiet ever since after i kept her away from anything runable for 2mth..that could quite easily of ruined a keen pup at such a young age..at the end of the day they is no rush.. do what everyone else has advised Dan and get all the training and stock breaking in order before you start chasing stuff