don't talk shit they are not meant to go to ground , they are there so when you break through to your terrier they can take over, its called not letting your terrier get the shit kicked out of it,
and as for being slow thats up to the lad, on what quarry he is going to take, with a 3/4 bred i don't think he will do much rabbiting with it.
thats y you must get the right tools for the job in hand