There's dogs for jobs the bitch we use is a good bolting dog , rocks all about the bolt as most can't be dug my mates bitch will stay hour or two if don't bolt she will come out drop back in most times get your bolt or some rock dogs will kill fox in , dogs can be lost in rock never tobe seen again , most stay away from rock piles as can be hard going dog in for days or weeks , not all terriers can work rock take a lot to work out an find in big piles or not built for the job