Eileen Spinelli, Linda Williams, , illus. by Megan Lloyd. . Harper-Collins, $15.95 (32pp) ISBN 978-0-06-028547-0

The horse wallowing in the pigpen is just the beginning of a girl's laughable lament in this rhyming barnyard romp by the creators of The Little Old Lady Who Was Not Afraid of Anything. When the youngster yells to her mother, "Horse is in the pigpen, rollin' in the slop," the woman calmly answers, "Tell it to the pigs, dear. It's time for me to mop." Thus begins a domino effect. Lloyd shows the horse on its back, wallowing like its porcine neighbors, and succeeding good-natured vignettes and full-bleed spreads portray the comical turn of events as one species displaces another. Finally, the girl finds the ducks (banished from their pond when the cat takes a swim) in the cow barn and—in the book's funniest image of all—the dozing bovine in her own bed. The mother then rises to the occasion, launching a reverse chain reaction that lands all of the critters back in their proper digs. Except one: a diminutive mouse that observant readers will have noticed lurking in preceding pages, whose antics just may launch the merry mayhem all over again. This farmyard frolic is sure to elicit gleeful groans of "Oh, no!" from young listeners. Ages 3-6. (Apr.)