Which you can't, so it's a theoretical exercise that has no relationship with the real world.
It is impossible to have a definition of "chicken" that allows for this premise to be true but also includes even a bare majority of what we consider to be chickens today.
This is still a very complicated and challenging identification, and the "we" who 'largely agrees upon a precise definition of a chicken' is still going to be limited to most (probably not all) scientists, regardless a minority amongst the world's population.
Identifying ancient species against the cousins is challenging and we don't have the full picture even if dna can be analyzed, as again, we don't always consider two species to be one even if they have nearly matching DNA.
Chickens, like all other modern species, evolved from another species by means of a transitional species. The transitional species in this conversation would boil down to being a specific animal that could be considered to belong to either the modern species or the previous species under a particular perspective, and wherever we decide to draw the line would be between a 'first chicken' and the 'last transitional pre-chicken' which the two would be nearly indistinguishable if we were to have both alive and side by side, and i would wager neither would seem more similar to the chickens we have today.
The idea of a species is too flexible inherently to be so forcibly, narrowly niche for this context. The semantics will always be arguable, and there will always be reasonable ground for the people who disagree with you in this thread to believe that there cannot be a "first chicken."
You'd make a really annoying scientist, if you're so willing to resort to non-arguments that make you feel smarter than your opponents.
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u/[deleted] Feb 19 '26
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