Herding breedss work by mimicking a predator to move the flock / herd around while other breeds guard the flock / herd from real predators with vigilance and, when needed, fighting them off.
Everyone has a job to do.
Here is one where the dog is moving the ducks into the pen. You can also see a gate in the background. The dog had to move the duck through that gate, out into the middle of the ring and then around another piece of fencing before coming to the center pen.
Then it was out of the pen and back to the holding area where the ducks were crated to rest while the next set came out for the next dog.
All this with a time limit and just some verbal cues and use of the staff as a giant conductor's baton.
You know, I did think about that a lot during the day. The sheep definitely acted more afraid than the ducks did.
There is a lot of effort put in to making sure none of the critters get hurt, but I'm sure they get scared. Not sure if I like that for "sport." On a real farm, with a real herd is a totally different story.
Edit: Oh, one of the things I learned was that a good performance has no running or chasing at all. It moves very slowly and the work is done from a distance. Of course, with the newer inexperienced dogs, there was a bit of running and chasing. The handlers that thought their dogs were getting too hyped up, pulled them off the field in the middle of the run.