Can a chicken egg be fully formed inside another?

* Egg Formation: A chicken egg is formed in the hen's oviduct. It starts with the yolk, which is released from the ovary. As the yolk travels down the oviduct, it receives layers of albumen (egg white), shell membranes, and finally, a hard shell.

* Space Constraints: There's simply not enough space within an already formed egg for another egg to develop. The egg shell is a hard, protective barrier.

* Reproductive Cycle: Hens lay one egg at a time. They typically have a 24-26 hour cycle for egg production, meaning a new egg starts its journey through the oviduct after the previous one has been laid.

However, there are some rare occurrences that might seem similar to an egg inside an egg:

* Double Yolks: Sometimes, a hen releases two yolks at once. This can create an egg with two yolks, but not a fully formed egg within an egg.

* Shell Abnormalities: Occasionally, an egg might have a thin or weak shell. If another egg begins to form, it might get trapped within the outer shell, leading to an appearance of an egg inside another.

Bottom Line: While there are some unusual situations, a fully formed chicken egg inside another chicken egg is biologically impossible.