In Zootopia, why was Dawn Bellwether (sheep) shown so small relative to other animals? In general, all animals preserved distinct proportions based on their kind but not her. She seems of the same size as rabbit Judy:
This is done in order to better provide the moral of the film.
The lamb is usually a symbol of innocence and, by size, looks, and behavior, Dawn Bellwether resembles more of a lamb than a sheep. It also triggers some protective instincts.
In the end we get the twist that
she is actually the mastermind behind it all.
So again the point is made that one should not rely on preconceived ideas.