As far as I can search nobody has published this pun* I improvisationally invented many years ago, when I was one of a group of trainees in a factory, and we spotted a tray full of sunny side up eggs in the cafeteria. So here it is:
Chickens of the world unite; you have nothing to lose but your yolks!
* The closest I could find was: Eggheads of the world unite etc.
