Marks and Spencer have announced that this weekend they will be launching cartons of British free range eggs with double yolks.
According to the British Egg Information Service, the probability of finding an egg with a double yolk is just one in 1,000, but the retailer has said that in the new six packs being launched, each egg will contain two or more yolks.
The British Egg Information Service says double yolk eggs tend to come from younger hens whose hormone systems have not yet fully developed. All the hens in a flock will be of a similar age, so it is not that unusual to find more than one double yolker in a box.
M&S will be using the method of 'candling' to determine how many yolks each egg contains. A bright light is put behind the egg so the contents can be seen; this technique is also used to check the edible qualities of an egg.
The egg's yolk is the 'nutritional centre' and contains vitamins such as B12 and B6, they are also one of the few foods to naturally contain vitamin D.
Ali Rodham, M&S product developer, said: "We're really excited to be selling double yolkers. We think they're cracking, and we're sure our customers will too."
"Perfect for people who think the yolk is the best bit of the egg, double yolkers are not only delicious, but they are healthy too."
The free range eggs will come in boxes of six and will be sold for £2.75.