I have kept terriers for more years than I care to remember, they will hunt a scent or blood trail no problem, but as said can be a pain going to ground, but like most things, what you put in you get out, my current border bitch is my wifes and I am not allowed to hunt her, you should see the change in her when she hits deer scent, I am lucky she has not shown interest in going to ground and has never been encouraged, if I was to use her for tracking it would be on a long tracking lead, great wee dogs and fun to have around.
Bod.