The exact definition doesn’t matter though, every chicken whether the first or the last, or from the blurry zone between proto-chicken and chicken, has many much older eggs in it’s ancestry. Probably somethig fish something.
The chicken (Gallus gallus domesticus) is a domesticated form of the red junglefowl (Gallus gallus), originally native to Southeast Asia. It was first domesticated around 8,000 years ago and is one of the most common and widespread domesticated animals in the world. Chickens are primarily kept for their meat and eggs, though they are also kept as pets.[1]
The red junglefowl (Gallus gallus), also known as the Indian red junglefowl (and formerly the bankiva or bankiva-fowl), is a species of tropical, galliform bird in the phasianid family, found across much of Southeast and parts of South Asia.
A species (pl. species) is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. It can be defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction.
You’ll have no problem citing the exact definition then.
The exact definition doesn’t matter though, every chicken whether the first or the last, or from the blurry zone between proto-chicken and chicken, has many much older eggs in it’s ancestry. Probably somethig fish something.
https://en.wikipedia.org/wiki/Chicken
https://en.wikipedia.org/wiki/Red_junglefowl
https://en.wikipedia.org/wiki/Species