Starfire by Jennifer Lynn Alvarez

Once every hundred years, a black foal is born, prophesied to either unite or destroy the five herds of flying horses that live in the land of Anok. He is fated to become the most powerful pegasus in all of Anok. Star is this black foal.

Even though Star has malformed wings that make him unable to fly, the leaders of each herd will take no risks and want to execute Star before his first birthday. With the help of his friends, Star must escape the clutches of the powerful leaders, and his epic journey of self-discovery turns into a battle between good and evil that will keep readers eagerly turning the pages.