i started all my pups off on long walks on rocks of easy scrambling mainly up the small streams comeing off the moors ,so they got used to the feel of them ,if they struggled behind the bigger rocks i didnt pick them up they worked their own way round them slowly learning to scramble & jump amongst them , entering them into easier piles knowing the safer ones to work ,obviously not entering them into the big piles , yes its a different way of working terriers , in my opinion any dog can work earths but not many earth dogs make excellent rock dogs , dont get me wrong some can & do work