Answer:
The whole flock runs away as a single group.
Explanation:
The sheep naturally leaves in rugged highlands and is well adapted for that terrain, and even there aren't many predators, the few that are present are also well adapted to the conditions and have mastered hunting them. In most cases, the best defense for a flock of sheep would be that they all run away as a single unit. The reason why this would be the best defense in most cases is the fact that a predator would not be able to single out a target, and also trying to attack a flock while running may end up with bad injuries because of kicks with the hooves and hits with the heads and horns.
Now while this is usually the best scenario, it needs to be taken into consideration the type of predator in question. If it is a single wolf, then the ram can stand up to it as it outweighs the average wolf by far, and has more than enough weaponsa and power to take it down and protect the heard, so standing as a single unit will work in this situation. If it is a snow leopard in queastion, a ram as well equiped and powerful as it is will still not be able to fend off the danger, so by protecting the heard will end up as the victim because of the immense strength, agility, and numerous weapons of the predator.