When this happens, the dog's drive and confidence around sheep increases constantly. Now is probably as good a time as any to discuss the importance of a proper education on the grip in a HGH herding dog. The most important thing to remember is to let the dog build confidence and drive on the boundary before putting it in a position to have to grip sheep. A good dog will instinctively know how and when to grip sheep appropriately out of confidence. And, when it does, the grip will be full and calm.
Any dog can try to grip a sheep out of fear or insecurity if forced into a position to do so.
But, when it does, the grip will in all likelihood be shallow, hectic and damaging to the sheep. I base this statement on my own experiences in schutzhund training and large flock boundary style herding, as well as on my observations of puppy tests on my own and Manfred Heyne's litters over the years.