[CarolinaGuitarman]

"No, merely noting that, per evolutionary theory, the first-whatever-we-now-call a chicken had parents who were not-quite-yet-what-we-call-chickens.

Hence, the egg came first."

From a taxonomic standpoint, the question is not answerable. The new species would only be evident after the fact, when the population that was speciating was at a point we could confidently call *chicken*. There would not be one member of that population though that you could point to and say, "This is the first chicken!". The entire population would be moving toward *chicken-hood*. This talk is making me hungry. :)

[MeanWestTexan]

Well, my line would be drawn where we could take a current chicken, have it mate with the ancestor, and if they have a viable offspring (that can itself reproduce), the ancestors's still a chicken.

The generation(s) before that, where you don't have viable offspring in such a time-machine mating, would be the not-quite-a-chicken.

Or, we could just cook it, to see if it tastes like chicken. :)