What causes an egg to have two yolks?

Introduction: What is a double-yolk egg?

A double-yolk egg is a type of egg that contains two yolks instead of one. It is relatively rare, with only one in a thousand eggs estimated to have two yolks. These eggs are larger than normal eggs and are often considered a novelty by some consumers. However, double-yolk eggs are not always desirable, as they can cause problems during incubation and may not hatch successfully.

Genetics: How does it happen?

Double-yolk eggs occur when two egg yolks are released from the hen’s ovary at the same time and are then encased in a single shell. This happens when the hen’s reproductive system is stimulated to release two eggs simultaneously, which can occur due to genetics or age. Double-yolk eggs are more common in young hens that are just starting to lay eggs or in hens that have been selectively bred for high egg production.

In some cases, double-yolk eggs may be the result of a genetic mutation that causes the hen to release multiple yolks in a single egg. However, this is relatively rare, and most double-yolk eggs are simply the result of a normal biological process.

Mary Allen

Written by Mary Allen

Hello, I'm Mary! I've cared for many pet species including dogs, cats, guinea pigs, fish, and bearded dragons. I also have ten pets of my own currently. I've written many topics in this space including how-tos, informational articles, care guides, breed guides, and more.

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