What do the sheep represent in the novel, The Wee Free Men?

Sheep symbolize the ordinary people of the land who are completely unaware of the many worlds which exist.

Sheep have been guarded by the Aching family for generations, and live their lives being herded by shepherds and sheepdogs. They do not know of any other existence, and neither do the majority of the people living on the land, including Tiffany herself at first. Her ancestors, she claims, "had been Aching to stay, not Aching to leave" (11), being tied to the land and unwilling to explore.

Tiffany realizes that, like a shepherd, she must use her power responsibly and not take advantage of the sheep, or the people.