Scientists Conclude the Chicken Came First — Not the Egg

For centuries, the question of “Which came first, the chicken or the egg?” has been a favorite philosophical riddle, used to spark debates and challenge the concept of cause and effect. It’s a question that blends science, philosophy, and a bit of humor. But now, modern science may have finally cracked the case — literally.

According to a group of researchers from the University of Sheffield and the University of Warwick in the United Kingdom, the answer is clear: the chicken came first. Their conclusion is based on the discovery that a vital protein used to create eggshells is found only in chickens, meaning the egg as we know it couldn’t exist without the chicken.

The Age-Old Question

The chicken-or-egg dilemma has puzzled people for thousands of years. In ancient Greece, philosophers like Aristotle debated it as a question of origins. Some saw it as a metaphor for life’s infinite loops, while others tried to solve it using logic. Even today, it’s a common way of expressing complex problems without obvious solutions.

But science, unlike philosophy, relies on evidence — and that’s exactly what researchers used to tackle the problem.

Cracking the Eggshell Mystery

The breakthrough came when scientists used advanced computing to study how chickens form eggshells. They focused on a specific protein called ovocleidin-17, or OC-17. This protein plays a crucial role in forming the hard shell that protects the developing chick inside the egg.

Using high-powered computer models and microscopic imaging, the researchers found that OC-17 acts as a catalyst during the formation of calcium carbonate crystals — the material that makes up the eggshell. Without this protein, the shell wouldn’t form properly. And here’s the critical part: OC-17 is produced only in a hen’s ovaries.

This means the biological machinery to create an eggshell — including the very first one — depends on a chicken’s body. Simply put, the egg could not have existed before the chicken, because the protein necessary to form the shell didn’t exist before chickens evolved.

So, What Does This Really Mean?

From a purely biological and chemical perspective, the findings suggest that the modern chicken — or at least a bird genetically very close to it — had to come first. This ancestor produced an egg using the OC-17 protein, and inside that egg was the first modern chicken. While the process of evolution is gradual, this moment marks a definable point at which the chicken, as we recognize it today, was born.

In other words, a bird very similar to a chicken laid an egg, but due to genetic mutation or natural selection, the creature that hatched from it was the first true chicken. But that egg — containing the first true chicken — still had to be formed by something that had the OC-17 protein. Therefore, the bird that produced that egg had to be very, very close to being a chicken already.

Evolution and the Chicken

Evolution helps explain how birds developed over millions of years from reptiles. Over time, tiny changes in DNA led to the development of different species, including chickens. Somewhere along that evolutionary chain, a creature nearly identical to a modern chicken developed the ability to produce OC-17. This tiny biological shift made it possible for the formation of the hard-shelled egg that chickens lay today.

That means the creature that made the first chicken egg wasn’t quite a chicken itself — but very close. Still, because it had the protein necessary to form the egg, and that protein is unique to chickens, the chicken had to come first in order to create the egg as we know it.

A Scientific Answer to a Philosophical Puzzle

While this might sound like a roundabout way to say both came first in some form, scientists are confident that, biologically speaking, the answer is the chicken. The egg needed the chicken’s unique protein to exist. Without that, no eggshell — and therefore, no egg as we know it — could have formed.

Of course, it’s important to note that this answer applies specifically to the modern chicken and its eggs. If we expand the question to ask, “Which came first, the bird or the egg?” the answer flips. Eggs existed long before chickens or even birds. Reptiles were laying eggs hundreds of millions of years before the first bird ever appeared on Earth.

Why This Matters

Beyond solving a fun riddle, this discovery helps scientists better understand how proteins control crystal formation — a process that’s important not just in biology but also in material science and medicine. Understanding how OC-17 creates eggshells could lead to advances in designing stronger materials or improving synthetic biominerals.

It also shows how deeply interconnected life’s building blocks are. A single protein can determine the structure of an egg and even shape our understanding of evolution and species development.

Conclusion

The mystery of whether the chicken or the egg came first has amused people for generations. Thanks to modern science, we now have a clear answer based on biology: the chicken came first. Specifically, a creature with the ability to produce the protein OC-17 laid the first egg containing a chicken — making the chicken, in a technical and evolutionary sense, the real starting point.

So next time someone brings up the age-old question, you can smile and say, “Science says it was the chicken — and there’s protein evidence to prove it.”