The age-old debate is finally cracked, and science says the chicken came first.

For centuries, people have asked: Which came first, the chicken or the egg? Now, scientists have an answer backed by biology, not philosophy.

The key lies in a protein called ovocleidin-17 (OC-17), which plays a crucial role in forming eggshells. This protein acts as a catalyst, helping calcium carbonate crystallize to create a hard shell. And here’s the clincher: OC-17 is exclusively found in the ovaries of hens.

That means eggshells simply can’t form without a chicken. No hen, no OC-17. No OC-17, no proper eggshell. Evolutionary logic follows that the bird (the chicken’s immediate ancestor) had to evolve first, developing the specialized biology to lay the kind of eggs we recognize today.

So, next time this question comes up in conversation, ditch the debate and drop the science: The chicken came first, literally hatched by evolution before it ever laid an egg.