General Discussion

The egg exists before fertilization so you'd have to either assume that all the mutations needed to make it a chicken occurred in the egg or that the act of fertilization turned the egg from a red junglefowl egg into a chicken egg (though it'd seem like the act of fertilization is about when you'd start separating the chicken from the egg). Someone could argue that the answer is a chicken, hatched from a red junglefowl egg, and it's probably a better answer.

Of course, as others have pointed out the real answer is that this is arguing nomenclature where no firm line of separation exists.