i first ran my dog on a young rabbit when it was 4 1/2 month old he caught it then done 1 and kept doin this for about 6 month it took me ages to get the dog right again and would deffo not reccomend it untill about 8 month at the earliest point to run it on quarry the dog will never get tired on retriving a siple lure or toy for me the most imortant thing for a working dog is to make sure the dog dose its job properly i.e chasing and retriving if caught obidients is 2nd to none the pup is still growing and learning it will chase any thing that move when its older dont worry about that all it