Can chickens have twins in one egg?

Here's why:

* One egg, one embryo: A chicken egg contains only one yolk, and a single embryo develops within that yolk.

* Separate eggs for multiple chicks: If a hen lays multiple eggs, each egg will contain a separate embryo.

* Rare exceptions: While incredibly rare, there have been documented cases of "double-yolked" eggs. These eggs contain two yolks, but the chances of both yolks developing into viable chicks are extremely low.

So, while it's impossible for a chicken to have twins in a single egg, they can certainly lay multiple eggs containing separate chicks!