Cock a Doodle Doo is a very old nursery rhyme. Actually it is almost 250 years old(!). Try to tell the kids how old this song is, they will get impressed! You might also tell them that the rhyme Cock a Doodle Doo was sung by their grand-grand-grand-grand-parents. Even before they had electricity...
Even though it is a old nursery rhyme, Cock a Doodle Doo is still used in many preschools/kindergartens all over USA and England.