Flautist and composer Anne McGinty (b. 1945) writes prolifically for bands of all levels, especially elementary and middle school. She studied at Ohio State University and Duquesne University, where Joseph Willcox Jenkins was among her teachers. Among many other honors in her career, she was the first female composer to be commissioned to write for the United States Army Band. She has her own publishing company, McGinty Music, specializing in chamber music for winds. See more about her at Wikipedia, Kjos, the Wind Repertory Project, and Barnhouse.
McGinty wrote All the Pretty Little Horses in 1998 based on what she calls “an American folk lullaby in minor mode.” It begins in 4/4 with eighth note figuration in the clarinets, surrounding the folk melody in filigree. The middle section changes key and puts the tune in 3/4, building to a stronger return of the initial filigree. It ends as gently as it began, fading to nothing.
You can learn more about McGinty’s piece (although for all its originality, she calls it an arrangement) at J. W. Pepper, the Wind Repertory Project, Kjos, and HeBu. The folk tune itself shares the name with the band piece, though it is sometimes also known as “Hush-a-bye.” Its origins are murky, but it is thought to come from an African American tradition, and it was first published in the earliest years of the twentieth century. Wikipedia and the Music for All Library have more to say about it. These two recordings are both worth a listen: