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How did the chicken come first if chickens come from eggs?

Asked by: Kiersten Godoy
School: Glenwood Elementary School; Vestal
Grade: 2
Teacher: Mrs. Summerfield
Hobbies/Interests: Riding horses, swimming and climbing trees. 
Career Interest: Veterinarian

Answer from Hiroki Sayama

Director, Collective Dynamics of Complex Systems Research Group, Binghamton University

Departments: Associate Professor, Bioengineering & Systems Science and Industrial Engineering.
Research area: Complex systems, artificial life, mathematical biology, computer and information sciences. 
PhD school: University of Tokyo
Interests/hobbies: Traveling, walking, swimming
Family: Wife, Mari; two sons (Takehiro - 13) and (Yukihiro - 9)
Web page address:

Great question Kiersten! This is a very old question, puzzling a number of people and making many scholars try to solve it using a variety of approaches, including philosophical, theological, scientific, and even mathematical. But I think I know a definite answer to this dilemma, at least from a biological viewpoint. My answer is, EGGS CAME FIRST. This means something very weird: At some time, the first chicken eggs must have been laid by animals that were not quite chickens. Is it possible?

Look at your parents, and then yourself in a mirror. Are you exactly the same as how your parents are? Maybe not. You may notice small differences, such as the shape of the face, shape of eyebrows, hair color, or even personality or food preference. This tells you an important fact: Children are slightly different from their parents. This is called "variation" in biology. Variations arise because some changes happen to genetic information when it is inherited from parents to children. 

(Just in case you didn't know -- genetic information is written in lengthy molecules called DNA, whose copies exist in almost all cells in your body. It determines how a living thing is shaped and behaves.)

Another important fact is that the genetic information will never change during an individual's life. So, the genetic information you have in your body cells today is the same as what you had when you were still a baby growing in your mom's pregnant belly. Genetically, you have been you, all the time, no matter what. 

These two facts are already enough to give a logical answer to your question. If genetic changes can't happen during a child's growth, it is not possible that "non-chicken" eggs grow into chickens. So, definitely, chickens can't come first. Meanwhile, genetic changes can and do happen when parents give birth to children, so it is a possibility that some non-chicken animals lay eggs that are genetically fully chicken. This must be the how chickens started. Nowadays those ancestors of chickens are thought to be red and grey jungle fowls -- wild types of chickens living in Asia that are not tame enough to be considered "chickens" as we know them. 

I must say, though, that it would be very hard to find out exactly when and where the first chicken eggs were laid. This is because there is no direct record available (note: the origin of chickens probably dates back several thousand years ago), and also because the border between what is a chicken and what is not is quite fuzzy. But these issues don't shake up our logical conclusion: Eggs must have come first, not chickens. Now you can brag about this knowledge to your family and friends. :)

Last Updated: 3/1/17