Question

What came first egg or hen

Answer 1

actually it's a bit confusing but still chordates came first which further evolved and like a hen.

Answer 2

So in a nutshell (or an eggshell, if you like), two birds that weren't really chickens created a chicken egg, and hence, we have an answer: The egg came first, and then it hatched a chicken. Maybe the question we should be asking is: Which came first, the proto-chicken or the proto-chicken egg?