I'd say, "The Chicken".

The question whether the chicken or egg came first can probably be most easily answered by people who believe that life begins at conception. Those people would believe that the chicken was conceived and just happened to have an egg around it until such time that it was ready to hatch. In other words, the egg should not be compared to the chicken because that's like comparing apples to oranges - or something like that.

People who accept the idea of evolution would likely assume that before the chicken was a chicken it was some other creature, which may or may not have had offspring that began life wrapped in an egg shell. Birds are not the only creatures who produce offspring in eggs. This would mean that before chickens were chickens they were other creatures that later evolved into chickens, which would mean that the - technically - chickens came first.

Of course, if you go way back to the very, very, beginning of when life began to grow on Earth before any creature could reproduce it would have had to have grown first; so, again, technically the chicken would have come first.

Yes - as far as I can see - all signs point to the chicken's having come first, even if the first chickens did not make their entrance looking like the creature we know today as chickens.