I am going to answer this definitively. I hate it when people ask this question like they are smart, or it is really philosophical.
Fossil records show that amphibians laid eggs LONG LONG LONG before the chicken ever existed.
Dinosaurs laid eggs. There were no chickens.
The egg came first.
So next time someone gets smart and asks this question. Look at them like the fool that they are, say 'the egg' and move on like they just asked as dumb of a question as they really just did.
Thank you.
Techincally, chicks are dinosaurs, so this argument is invalid.
Nothing to see here people, move along.