Scotsgirl - I have a collie x lurcher here, or rather a lurcher with collie on both her sire and dams side. The problem with trying to train a lurcher for herding, is that ultimately herding is just a version of hunting, where you are playing upon the dogs (collies) hunting drive, they are part of a hunt, driving the sheep (the quarry) to the alpha animal (you) to deal with. This works well, because we have harnessed this form of prey/hunt drive in such a way for generations. However, with lurchers, we have harnessed a slightly different form of this prey drive, and in a different way. My lurcher is broken to all stock, sheep included, but if I encouraged her to work them, her version of 'work', would be to catch, rather than to drive. The sighthound in her would push her to chase and single out, rather than to push them toward the alpha member of the pack. Of course it could work, but in my opinion it would be hard training and you would get a fair few sticky mess ups, where you had encouraged your running dog to 'hunt' sheep . . . . . . . . . and then had to deal with the aftermath!