The Unkindness of Ravens by John Ryland

Overlooked by grief-stricken parents, 13-year-old Miranda follows a raven into the woods behind her house. When it leads her to the dead body of a young boy, her past awakens in ways she could never imagine. After deciding to keep the body a secret and taking on the role of protector, she realizes that the remaining flock of ravens also have their sights set on the body, whom she has named Andy. Haunted by memory fragments of the death of her younger brother, the desire to protect Andy quickly becomes an obsession, and so do the ravens. Fortunately, Miranda knows just how to deal with birds who can't keep a secret.