I think this sums it up really
http://www.thehuntinglife.com/forums/index.php?showtopic=135065
nice dog what is his breeding mine is a 3/4 grey 1/8 bull 1/8 collie
friend of mine had a collie whip grey she got hurt real bad and done her back leg (ligerments) took a good while 8 weeks plus she ran 1 rabbit and came back limping it took loads of rest and slow walking to build the muscle back up around it and she was ok but not the same as before .all the best with your dog hope a good recovery