Five O'Clock Charlie by Marguerite Henry illustrated by Wesley Dennis*

I loved this book as a child.  So I was excited to share my childhood copy with my preschooler.  He "sort of liked it"!
I still highly recommend it-great vocabulary, figurative language and a must for horse lovers and those who love England.
Charlie is a retired work horse who must live out the rest of his years eating thistles and chickweed in an old field.  The worse part about retirement is not being able to trot to the Boar's Head Inn for his daily apple tart.  He finally has had enough and takes matter into his own  hands . . .then life once again has meaning.
*Highly recommend.

Warning: The author mentions Birdie's (the cook at Boar's Head Inn) rather robust bosom.  Another sentence has, "she always jumped and grabbed herself as if an icicle had dropped down her bosom."  It creates a rather vivid picture and a humorous one.  I skipped over it when reading aloud to my child who cannot read.