The chicken obviously came first who else laid the egg. I say to Graham trying to "egg" him on. "Well, it's really logical, the chicken couldn't have happened without an egg, so the egg came first."
But Graham, who laid the first egg? "The first egg was laid by some chickenduck creature, not really a chicken, the creature that existed before chickens."
Ahh so that's the answer then...the chickenduck came first.