A chicken egg must come from a chicken in order for it to be a chicken's egg. But a chicken doesn't have to come from a chicken egg because the egg could could be the egg of an ancient chicken, which is not defined "Chicken" as our modern chicken. So our modern chicken could be the mutation of an earlier chicken, and therefore it came before the egg.
A chicken egg must come from a chicken in order for it to be a chicken's egg. But a chicken doesn't have to come from a chicken egg because the egg could could be the egg of an ancient chicken, which is not defined "Chicken" as our modern chicken. So our modern chicken could be the mutation of an earlier chicken, and therefore it came before the egg.
He didn't ask whether the chicken or the chicken egg came first. He asked if the chicken or the egg came first.
A chicken egg must come from a chicken in order for it to be a chicken's egg. But a chicken doesn't have to come from a chicken egg because the egg could could be the egg of an ancient chicken, which is not defined "Chicken" as our modern chicken. So our modern chicken could be the mutation of an earlier chicken, and therefore it came before the egg.
Just a matter of definition.
If you define a "chicken egg" as an egg "containing a chicken" instead of "produced by a chicken", the egg should be first.