Horses disturbed by a motorbike run away - interesting herd dynamics

There was a noisy motorbike by the paddock that was scaring some of the horses. Penny led the fray, being a nervous Nelly and they all soon ran off with the herd leader, Halo taking them to the other end of the paddock.
It was interesting to watch them relax and start returning to where they started. Interesting herd dynamics.
Some swearing.