I Bet that Chicken was Screaming--- Or Alien

[jeff of pa]

So we came home Wednesday evening and Erik showed me the gigantic egg he found in one of the chicken nesting boxes! The kids have been so excited to see what's inside of it....so I thought it would be fun to turn on the camera and include all of you! We can find out together! Sometimes, new egg layers lay some odd eggs.

 

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[Red-Coat]

Fascinating! This, edited from the ‘Backyard Poultry’ website:

Though quite rare, it is well-known that occasionally a hen will lay an egg inside of an egg. The cause of this phenomenon is called a counter-peristalsis contraction and occurs while the hen is in the process of forming an egg in her oviduct.

A hen typically releases an oocyte (the ovum that becomes the yolk of an egg) from her left ovary into the oviduct every 18-26 hours. The oocyte travels slowly through the oviduct organ adding layers of the egg along the path to the chicken’s vent from which it will lay the egg.

A counter-peristalsis contraction is when a second oocyte is released by the ovary before the first egg has completely traveled through the oviduct and been laid. The release of a second oocyte into the oviduct system while a first oocyte is in the eggshell-gland portion of the oviduct causes a contraction. This counter-peristalsis contraction, resulting from the premature release of a second oocyte into the oviduct, causes the first egg in the eggshell gland to reverse its course and be pushed back up to the top of the oviduct. Consequently, the first egg is typically added to the oocyte that was just released into the oviduct. The second oocyte then travels down the oviduct and has albumen and a shell deposited over it and first egg together. This creates a very large egg for your poor hen to lay. When you crack open such an egg, there is normal yolk and whites as well as another fully formed, normal-sized egg inside.

How a Chicken Lays an Egg Inside of an Egg - Backyard Poultry

Occasionally, a hen will lay an egg inside of an egg, a phenomenon called counter-peristalsis contraction, and it occurs while the hen is forming an egg in her oviduct.

backyardpoultry.iamcountryside.com

 

[xr7ator]

Interesting. Anyone notice the different shades color in the egg, making it look like maybe it took more than a day to lay?
About 50 years ago we had a friend up the street with a farm and chickens. (they had a gorilla and a loin as well...but another story!) They had a hen that laid an egg and was similar in size but you could see three different shades and there were almost lines between the shades...more pronounced than the above example. The family said it took three days for the egg to pass and the hen that laid it had a bloody behind for a day or so afterwards.
They held onto it for show and after some time decided to eat it. We all thought it would have three yolks, but it didn't. It was just one big egg and no egg inside of an egg. They broke the side of the shell to get the egg out and kept the shell for show.
I would have never guessed another egg inside. Thanks for posting, Jeff.

 

[jeff of pa]

I Always wonder if Double Yolks if Hatched Create Twins or Siamese Freaks

 

[Red-Coat]

I Always wonder if Double Yolks if Hatched Create Twins or Siamese Freaks

You get twins. Usually, one embryo out-competes the other and only one survives. Sometimes they're both weaklings, and neither survives.