Well, i think if you believe in evolution, then the obvious answer is the egg. If you believe in ID or creationism (whichever you perfer), then the obvious answer is the chicken. if you don't know, then this sounds like a trick question

i found proof!

Higher power, other than nature=chicken

A "common" power, nature, or other forces at work here on this planet=egg

Just think of it this way: which genetic mechanism is going to evolve in a creature? Laying eggs or being born in eggs? Necessarily, the genetic component for laying them had to exist before any were born in one. Which seems to point to "Chicken."

But then you get into what defines a chicken: birds came from lizards, so they were probably laying eggs before we would call them chickens. So, egg.

EDIT: Damn, I guess that was explained in your article already. Oh, well. Convergent thinking gives it more credence, then.

Dinosaurs laid eggs.

Well, it’s still unclear whether chicken eggs or chickens came first (the intended question in the original riddle), said Darla Zelenitsky, a paleontologist of the University of Calgary in Alberta who was the first scientist to closely analyze the dinosaur nest.

But interpreted literally, the answer to the riddle is clear. Dinosaurs were forming bird-like nests and laying bird-like eggs long before birds (including chickens) evolved from dinosaurs.

"The egg came before the chicken," Zelenitsky said. "Chickens evolved well after the meat-eating dinosaurs that laid these eggs."

So the original riddle might now be rephrased: Which came first, the dinosaur or the egg? Meanwhile, the new nest provides some of the strongest evidence in North America in favor of the bird-like egg over the chicken.

It would have been the egg. There were eggs way before birds and definitely way before chickens. I think that the question is asking in general what came first. Well the first creatures were microscopic creatures. As time went along the creatures evolved ( yes I am going with evolution ) into different creatures finally giving birth to a reptile which laid eggs. Then a millennia later the first chicken came from the offspring of birds. So the egg came first.

SCIENCE IS BORING!

Adam was made first, right?