The investigation was launched after some consumers said
they bought the "artificial" eggs made by traders seeking profits,
the China Daily said.
But food experts said the eggs were likely to be natural.
Their unusual characteristics could be explained by high levels of a compound
When egg-laying hens eat gossypol-enriched feed, it binds to
the protein in egg yolks.
Gossypol normally exists in the residue of cotton seeds
added to chicken feed as an extra protein source.
Experts say large doses of the compound suppress sperm
activity. Gossypol has been used in male contraceptive pills in a couple of