Well obviously an egg, becasue chicken came out from it. You'll ask "and where the egg came from? Obviously it was layed by a chicken!". and I can answer you that it was layer by a primodal flightless bird that was a chicken's anchestor and altrough it's genome was similar, you couldn't call it a chicken, but it's child, the egg, had laready evolved into chicken.
Now seriously this discussion was unencesseary and obvious, now when I have proven how smart and modest I am I shall report this thread to get clsed for it's unnecesearity.