A lot of ink has been spilt over the question of whether the chicken or the egg came first. (And probably more has been spilt using it as a metaphor for a pointless or unanswerable question.)
People have tried to find the answer by appealing to religion, to philosophy, or to science. Perhaps the best answer is a linguistic one: "the chicken" comes first in the text of the question.
Here's one possibility that I haven't seen discussed: what if they started out as the same thing? What if the egg-chicken came first? Over time a population of egg-chickens diverged until one lineage became eggs and the other lineage became chickens. And the chickens are now brood parasites—whenever they find an egg, they put a chicken embryo in it. The egg, not realizing what has happened, raises the embryo until it's a chick. At that point the chick destroys its host as it emerges from the egg.
Here are some hypothetical reconstructions of what the original egg-chickens looked like.
These illustrations were drawn using Stable Diffusion 2.1.
