Flight zones and moving sheep

Sheep are prey animals and prey animals have a flight zone. The flight zone of an animal is the area surrounding an animal that if encroached upon by a potential predator or threat, including humans, will cause alarm and escape behavior. 

We can use this to manage, move or muster sheep in a safe way in a paddock or in yards.

https://www.grandin.com/behaviour/principles/flight.zone.html