I don't know enough about sheep social dynamics to care but... In my experience humans also work like this in friend/family groups.

Families and friendships groups usually have one or two "leaders" who do most of the social "admin" (eg, arranging gatherings between the friends) but the actual "lead" of the group is flexible and situational. People defer to the trusted person who has most experience with a particular problem, and unorganised decisions happen organically (like, when it's time to leave).

I only ever see it on a really small scale though, like maybe a dozen people? Sheep flocks are bigger, but then is guess their social dynamics are much simpler so the same mechanism can be used over larger group. And since they have no way of improving their methodology, groups that get too big to work by this method will break up into manageable groups again.