I’ve been to see loads of sheepdog trials, and watched dogs rounding up sheep on the hills plenty of times. Don’t let the videos kid you — most of the time, either the dog or the human fucks it up. Not in a major way — although in one trial I saw, I did once see a dog grip a sheep, which, when let go, then legged it over the nearest hedge closely pursued by the dog. But the vast majority of the trials I’ve watched have ended in failure. And on the hills, there are a lot of false starts. (And I note that the posted video has been heavily edited!)