Crack The Big Egg

A farmer discovered a brown egg laid by one of his chickens that was much larger than the size of a normal egg. He cracked open the egg to find one egg, plus another shelled egg inside.http://www.youtube.com/watch?v=_wubgAIiWpY

The event was captured on video and circulated the Internet in September of 2009.http://www.youtube.com/watch?v=_wubgAIiWpY The video was commonly known as "Crack the Big Egg."

The phenomenon at hand is a very rare condition for egg laying called a Double Shelled egg. An egg within an egg, or a double shelled egg "appears when an egg that is nearly ready to be laid reverses direction and gets a new layer of albumen covered by a second shell".http://www.poultryhelp.com/oddeggs.html

For this rare condition, according to Poultry Help, "the reversed egg joins up with the next egg and the two are encased together within a new shell". Double shelled eggs are so rare that no one knows exactly why or how they happen. At times, the egg found inside the other has no yolk, while the egg in the video did have two yolks. http://www.poultryhelp.com/oddeggs.html

According to the International Dove society, "double shell eggs occur when one egg hatches and the parents have not removed it. The egg is inside the hatched egg shell . In this scenario, an infertile egg is slightly smaller; allowing the hatched egg shell to slip over one end. This in no way caused the infertility of the egg."http://www.internationaldovesociety.com/RNColorPics/doubleeggshell.htm

When double egg shells occur on a farm, most of the time, the hatched egg shell is not immediately removed by the parents. The subsequent movement and re-adjustment of the other egg and baby causes the larger end of the hatched egg shell to slip over one end of the other egg in the nest. Provided that the other egg was fertile, the baby could have trouble trying to hatch; it would not have the strength to pip through both egg shells, if the second egg shell was covering the hatching end.http://www.internationaldovesociety.com/RNColorPics/doubleeggshell.htm

For farmers, leaving the infertile egg or hatched egg shell in the nest with a single youngster is optimal, since it keeps the parents from smoldering the newly hatched young (for any number of reasons). Additionally, the youngster has something to rest it head upon.http://www.internationaldovesociety.com/RNColorPics/doubleeggshell.htm