The Postlethwaite family lives in Stoke-on-Trent, Staffordshire, UK. They have 4 hens at home. One of them laid a massive egg weighing 5.9 ounces. When Emma, the mother in the family, cracked it open to fry it, there was another whole egg inside! You can watch the family's adorable reaction in this video.
How did this happen? The Herald Express explains that a chicken ovary may release an egg prematurely, causing it to envelop the previously-released egg cell:
The extremely rare occurence is known as a counter-peristalsis contraction and is caused when the hen is in the process of forming an egg in her oviduct and another oocyte - the ovum or egg cell that becomes the yolk of the egg - is released too soon.
Usually hens release an egg cell every 18 to 26 hours but sometimes a second one is released by the ovary before the first egg has completed its journey.
It is thought that a shock or stress then causes a contraction which forces the first egg to reverse its course meaning the two come together and the shell from the second egg creates a giant egg around the first one.
Have you ever encountered an egg within an egg like this one?