Obviously the chicken. From a religious standpoint, God made the chicken. From an evolutionary standpoint, the chicken still came first because the egg wouldn't be able to survive on its own, in both the chick form and the egg form. And if it could survive on its own, how come it needs an incubator (of any type, including the mother) to hatch these days? That would mean it devolved. It also doesn't make sense why sludge or fish or w/e would turn into an egg rather than a chicken. I don't see the big debate about this topic :P
btw, before anyone says anything, there was more than 1 chicken but the chicken still came first
An egg cant protect itself. So its most likely the chicken came first.
Then again through evolution its more likely the creature it was before it evolved would have taken care of the egg. But then again it would be considered a chicken now would it?