The Fourth Pony Pal(2002)
(The fourth book in the Pony Pals Super Special series)
A novel by Jeanne Betancourt
After arriving at the jumping clinic, Pam, Anna, and Lulu are upset that they will be separated, and the situation becomes even more disturbing when they discover that something may have happened to Pam's roommate's pony.
Used availability for Jeanne Betancourt's The Fourth Pony Pal
January 2002 : USA Paperback