Gertie the Hen "Sex-Changes" into Bertie the Rooster

By Patrick Morgan | April 19, 2011 2:46 pm

Normally, chicken-keepers don’t sweat it when their hens go through short egg-laying dry-spells. But when an egg-less hen grows a wattle in a matter of weeks and starts crowing at the rising sun, it may be time to worry. That’s what went through a British couple’s minds this past year, when their pet hen Gertie began looking and acting like a rooster.

It all started last November, when Jim and Jeanette Howard of Huntingdon, England, noticed that Gertie stopped laying eggs. “Then a few days later I heard her try to crow,” Jeanette Howard told the BBC. “She wasn’t very good at it at first, but she’s progressed nicely.” Gertie then got heavier and developed a wattle under her chin in the next few weeks. And as her feathers grew back during her molt, they were a darker brown than before. Sporting a scarlet cockscomb and a rooster-like strut, Gertie is now outwardly indistinguishable from a cockerel.So how did this happen? There are still many unanswered questions about Gertie’s apparent sex-change, but according to Poultry Club of Great Britain member Victoria Roberts, Gertie’s change is “a one in 10,000 event caused by changes in the bird’s hormones.” As veterinary surgeon Marion Ford told the BBC, stored animal feed can sometimes harbor fungi that acts as a synthetic hormone: “An increase in testosterone will result in a hen growing an extended comb, exaggerated wattles and cockerel-like behavior, including strutting and crowing.”

Keep in mind that this may not be a “real” sex change: These changes may be only outward, or phenotypical, with Gertie remaining a genetically female chicken.The fact that hormones might be the cause of Gertie’s outward sex change is especially weird in light of recent research that shows that a chicken’s cells are either inherently male or female, regardless of the hormones involved. So how did hormones interact with Gertie’s “inherently female” cells to make her look and act like a male? We’re not sure. But as far as Jeanette Howard is concerned, Gertie is a male, and as she told The Sun: “I shall have to stop calling her Gertie now and start calling him Bertie.”

Related Content:
DISCOVER: Sex Secrets of the Bi-Gender Chicken
80beats: For Sexually Confused Chickens, The Answer Is in Their Cells
Discoblog: The Amazing Sex Lives of Coral: Girls To Boys, And Then Back Again
Not Exactly Rocket Science: Gut bacteria change the sexual preferences of fruit flies
Not Exactly Rocket Science: How the Transylvanian naked neck chicken got its naked neck

Image: flickr / raymondgobis

MORE ABOUT: gender, genetics, hormones, sex
  • Zora

    Very interesting. I do have to say that I’m not sure about the use of “real” here (“real” sex change) – the way you word it, it sounds as if you are suggesting that anything but genetic change isn’t actually a sex change. That is true only if you define sex purely on a genetic level, and it’s also all too easy to make the leap from this to invalidating the sex-change processes that humans go through as part of gender reassignment. (Part of the issue is of course that we often say “sex” when we mean “gender,” but we do also have multiple definitions of what “sex” means, depending on whether you’re talking to a geneticist or a biologist, or even a plastic surgeon.) I don’t think that you intend anyone to make that mental leap, but I also read this blog (and other science blogs) frequently. But for people who get here because someone else re-posted on Facebook, who may not be familiar with this blog but may be familiar with many attempts to deny the validity of transgender experiences, it could easily be misunderstood. (That denial is pretty common, after all.)

    Gods, I feel like the PC police over here and I don’t mean to be. I’m just imagining myself in the shoes of friends who don’t regularly read this blog, and I just want you and all my friends to get along!


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!


Quirky, funny, and surprising science news from the edge of the known universe.

See More

Collapse bottom bar