LONDON (Reuters) - A flock of sheep charged a British farmer`s wife bringing them food and pushed her over a cliff to her death. Betty Stobbs, 67, had taken a bale of hay on the back of a power bike to feed the animals grazing in a field overlooking a disused quarry. The sheep rushed forward and jumped up onto the vehicle, knocking the bike and its rider over the edge of the quarry near Durham, north-east England. "I saw the sheep surround the bike. The next thing she was tumbling down the incline," neighbour Alan Renfry told reporters. Stobbs died when the bike fell on top of her.