The scientists have proved, and the archeologists have proved that the chicken came before the egg. As most land animals evolved from the sea, which was acidic at that time, try putting an egg into a glass full of vinegar, and see what happens.
I think that you and Space Cat have provided the key to the solution. In particular that at some stage in the overall process something emerged from it's shell that was defined to be the first chicken and that all subsequent eggs could be referred to as a chicken's egg. The Egg that gave birth to this first chicken was (by definition) not laid by a chicken as the chicken had yet to be born, and therefore could not be called a"chicken laid egg".
It is also entirely possible that the egg in question happened to be able to survive in the acidic environment to which you refer, but the creature that came out (the first chicken) could only lay eggs that didn't have this property.
