My supermarket sells eggs that are guaranteed to have double yolks, but this is surely a random process. What are the chances of a double yolk, and how do egg producers ensure there are enough to fill their boxes? Can they engineer them via artificial means? My local supermarket always seems to have a plentiful supply so presumably it鈥檚 easy enough to find or generate them.
Patrick Ness, Maidstone, Kent, UK