Time to put on the asbestos suit.
If one subscribes to the theory of evolution, it follows that the mother of the first chicken was not a chicken. Ergo, the egg came first.
It’s rather obvious that the egg came before the chicken. The “chicken” can be traced back to about 600bc and we know that it was a cross between a red jungle fowl and a grey jungle fowl. There were plenty of creatures that laid eggs before someone domesticated jungle fowl.