They are either the precious treasure(s) of an adoring parent or caregiver who is entrusted with ensuring that no harm befalls the living creature developing inside or they serve as the transitory dwelling place of a charming critter who is either a) lost b) in danger c) looking for its real parents or d) all of the above.
It is a formula that works, especially when the illustrator adds subtle nuances and ticks to the new born babe. Consider for instance the lost little chick in Are You My Mother by P.D. Eastman. With his spindly legs and inquisitive manner we quickly fall in love and hope against hope that this darling will find his real mom (he does).
This was one of the first books I had to sign to a preschool class when I was student teaching 14 years ago and boy was I nervous. I kept signing "Are you my father" instead of mother.
Eggs can also be found in the Caldecott winning children's book Make Way for Ducklings by Robert McCloskey. In it Mr. and Mrs. Mallard go from hatching eggs to tending chicks all the while exploring Boston Public Garden. Classic, amazing book.
Then there is the young adult literature of Eragon by the precocious young author Christopher Paolini that begins when the young hero finds a dragon egg for which he sacrifices much and cherishes beyond all things (I never made it past page 289 and I really wanted to like it).
Of course this time of year egg books abound as the Easter Bunny hippity hops his way to the baskets of some boys and girls.
There is Bunny Trouble by Hans Wilhelm about a soccer obsessed hare named Ralph who finds his place in the egg painting/decorating business after a rough start.
And Easter Mice! by Bethany Roberts. An Easter egg hunt that finds the most, the biggest and the BEST eggs hidden in the grass.
Sample text: "CRACK! Surprise! An Easter Friend!" The last egg hatched a baby turtle. The 5 and 6-year-olds loved this!
Thinking back, I may have to amend my previous statement. Maybe eggs do get fried in children's books every so often.
Consider Green Eggs and Ham by Dr. Seuss. But then again, they are green and perhaps not the kind that would spring to life adorable little offspring. I guess we'll never know.
The top picture is taken from The Peace Book by Todd Parr. The caption that accompanies it reads "Peace is keeping someone warm".