Even with this perfect definition there are still ambiguities. You could still debate if a non-chicken egg with chicken DNA is a chicken egg. Its shell and yol

Even with this perfect definition there are still ambiguities. You could still debate if a non-chicken egg with chicken DNA is a chicken egg. Its shell and yolk, all contents, were produced by a non-chicken - imagine the eggshell was blue, not white, and the final allele change to become “chicken” switched the “egg color laid once grown” to white. If all this eggs contents were produced by a genetically non-chicken - the egg is blue - is it really a “chicken egg”? Imagine you took a chicken egg, and modified the DNA so that an elephant would hatch. Is this a “chicken egg (with elephant DNA)” or an “elephant egg (with shell, white, and yolk produced by a chicken)”?