This is an article that was bound to happen at some point (even if the question was probably not meant to be taken too seriously): which came first, the chicken or the egg? Many consider this age-old enigma to be impossible to answer. Those folks might be in for a surprise.
In short, the egg came first, for before chicken other vertebrates did lay eggs. The first ones were fish, after them came amphibians. So the egg did beat the chicken by hundreds of millions of years. But what about the classic chicken egg we know today? Surely one can never know that, right?
Well… to reproduce on land, animals needed to keep their embryos wet at dry land. About 334 million years ago, Casineria was probably one of the first who managed to do so, laying eggs likely encased in leathery shells. That way, the fluids were kept inside the egg. Later, the Tree of Life branched out into the family of the Sauropsids to which dinosaurs, birds – and yes, chicken, too – belong. 
As such evolution takes many lifetimes, the changes from one generation to the next are infinitesimally small. Therefore, the transformation from one species into the next is very gradual, a fact that our binary classification system cannot really represent. But at some point, a bird that was not quite a chicken yet but very close to being one laid an egg. And from that egg the first bird that met all conditions to be classified as a true chicken hatched. 
So the egg was really first.
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