The following is an excerpt.
Given the chicken’s agricultural importance, scientists long knew that, like 97% of bird species, roosters didn’t have a significant penis—at least, not one large enough to deliver semen deep inside a female’s reproductive tract. And a new study published today in Current Biology found that the activity of a single gene is enough to literally dis-member a chicken’s penis during embryonic development.
Read the full story here: Single Gene Explains How the Rooster Lost His Penis
