I noticed that this book was originally written and published in 1982 and that might explain why it seemed a little dated.  The illustrations are cheerful, highly detailed and colorful.    In this story Mrs. Hen’s egg rolls out the her next and down a hole.  Friend Pakkun the wolf (he doesn’t resemble any kind of wolf I’ve ever seen) volunteers to go and get it.  Underground he encounters strange creatures and they go to sea where he swims with other strange creatures.  They go to dinosaur land and meet Mr. T Rex, who is friendly beyond belief.  They finally travel up Mt. Sulfur and in a cave find the ground littered with eggs, all starting to hatch.  Mrs. Hen’s egg is the smallest and he takes it back to her above ground.  All is well.  Kids will enjoy looking at all the details.