Number One Sam (Disney Hyperion, 2014) by Greg Pizzoli is a fast, fun read. Sam, a dog, is number one at the races. He's used to winning. Until his friend Maggie, an elephant, comes in first. At the next race, Sam has to make a choice about winning or losing.
This book got a starred review in Publisher's Weekly and has been chosen as Pennsylvania's One Book, Every Child selection for 2015. At about 300 words is a good short picture book to study for writers and an easy book for beginning readers.