The New Pony by Catherine Hapka
The Pony Scouts are becoming better at riding with every lesson. But just when they think they've seen it all, a new horse arrives on Jill's farm—one who hasn't been ridden before!
Taffy is a beautiful palomino pony that needs Jill's help. With a little patience and a lot of love, Jill and the Pony Scouts will make Taffy a member of the family.
The Pony Scouts series is full of all the rich details young horse lovers devour, from pony-centric plots to a "Pony Pointers" vocabulary page at the end of each book. 
This is a reading level 2 in the “I Can Read!” program.

Paperback book, 32 pages,
Measures 6 x 9” to fit small hands