Tuesday, October 22, 2013

Unclear Gender/Sex? Is My Chicken an Hermaphrodite? The Story of the Gynandromorph Chicken

She looked like a pullet... up until she didn't look like a pullet. But now she doesn't quite look like a rooster, either. What is going on?? At first this chicken's gender was very unclear!

Scientists believe that Gynandromorphism in chickens happens when two sperm fertilize the same egg. It is somewhat rare, happening in 1 of every 10,000 chickens. If you meet enough chicken people, sooner or later you will hear tales of a chicken of questionable sex. And as it so happens, you are currently reading a story on a blog of someone who has a Chicken Of Questionable Sex... so we'll just call this chicken "Coques" for now.

Meet Coques:

Showing his/her girly side. No - I mean really. This just may be the female side of the bird!

As of the writing of this article, Coques is about 23 weeks old. As you can see, s/he has no noticeable saddle feathers. If you look closely, you can see that the tail feathers on this side are rounded, set at an angle and quite pulletish. But look at the tips of the tail feathers you can just make out on the other side... they are sickle feathers!

Can you see the difference?

I knew there was something different about this bird from early in his/her chickhood, but at that time I just thought him/her to be a special needs chick, and that perhaps it had experienced incubation issues and lack of proper nutrition with it's original owner (who fed it low-protein layer feed for it's first couple months of life).

One of the first things I noticed was that s/he was lopsided. Yes - the tail goes to one side, as does the neck, and it runs in the goofiest, klutziest manner I've ever seen.

 Yes - the tail always leans to the left... probably because of the different kinds of feathers coming in on each side.

 Here is where you can actually see a color difference between the two halves of this bird. This difference would be much more pronounced in unmottled breeds where the roosters have different color plumage than hens. Is that cool or what?

I likely would have given this bird away to a pet home had it not been for his/her endearing personality. S/he is by far the friendliest chicken I have ever had.

Yes - this is the chicken that dutifully oversaw my recovery from wrist surgery, and that runs up and right into my hands the moment I step foot outside. No - I never gave him/her treats to teach this behavior... s/he just loves to be cuddled.

Now just for comparison purposes, I'm going to share photos of Coques' full sister (same mother and father). We'll just call this bird "Grace."


 Grace (left) and umm... Disgrace... (right)

 Grace - being graceful.

Coques - being "squawkward."

I don't know how Coques will change as s/he gets older. It will be interesting to watch his/her development to say the least. I also don't know how this condition might suppress hormones. While Coques does have sickle feathers coming in on his/her male side, there is little development of either saddle feathers or hackle feathers (at this time). S/he does have a few shiny mahogany feathers here and there (a male trait) but they are few and far between.

  For comparison: Mace is Coques' half-brother (same father), and just 10 weeks older. You can see how noticeable the saddle and hackle feathers are on this roo.

 Coques hatched without a toenail on the female side foot. I don't know if this has anything at all to do with the gynandromorphism or if it was an incubation issue.

There are two forms of gynandromorphism - bilateral gynandromorphism and mosaic gynandromorphism. In bilateral gynandromorphism the body is divided neatly in half - one full half of the body will express features from one gender while the other half of the body expresses features of the other gender. 

Mosaic gynandromorphism expresses more like a patchwork quilt with different areas expressing gender-specific features over the whole body.

(I don't know for sure if Coques is a bilateral or mosaic gynandromorph - perhaps time will tell.)

Both kinds of gynandromorphism happen while the developing embryo is at the very first stages of cell division. It only occurs  in birds, crustaceans and certain insects - mammalian hormones do not allow for the body to develop in a gynandromorphic  manner, but a similar condition called Chimerism does affect mammals in very rare cases.

 As for now, Coques is smaller than other chickens his/her age (even the Silkies). It is likely s/he may never lay an egg or crow, although it is possible s/he could do both. Needless to say, I will not be using him/her in my breeding program, but if s/he stays as friendly as s/he has been up until now, s/he will have a forever home with me!

For more on gynandromorphism (and to see some really striking photos) see:

*Chicken names have been changed to maintain privacy


  1. OK found my glasses. Sorry to any who read my deleted, incomplete comments. LOL

    First, if its bilateral, then the roo side would dominate, since a hen's single ovary is on the left, as are the sickle feathers on this bird. If it's mosaic, then anything's possible.

    The second thought is, it doesn't matter how many sperm fertilize an egg, that would only cause same sex differences, like maybe changes in color or patterns, but the sex would be one or the other. It's the HEN who determines the sex. So with this bird, more likely it was 2 separate ova that were combined on the surface of one yolk and then both fertilized.

    Normally each ovum is given it's own yolk separately, and fertilization occurs when it's time to add albumen, membranes and shell. So in this case, you have two ova placed on the yolk fairly close to each other. Both were fertilized, and as the cell mass grew it merged and the two embryos became one. When the cells start becoming specialized and differentiated, there is nothing telling them that only some belong to one bird and some to the other. Kind of the opposite of identical twins where the embryo divides prior to cell differentiation. The difference being, if you have both sexes present, then the offspring may show signs of both.

    It is quite possible this happens more often than people realize, but both ova are of the same sex/breed/variety/whatever. Unless you notice something 'off' there's no reason to suspect anything out of the ordinary.

    Ok, my thoughts are completed, the glasses are coming off and I'm going to take a nap now. LOL Thinking is tiring.

    Karen - ki4got

  2. Very interesting! I guess Coques is a lifer at the farm. It will be interesting following his'ers story.

  3. That is totally insane! It said one in 10,000 out there in one of those articles. Maybe you should get a lottery ticket :D (Just sayin')

    You'll have to keep us updated on whether you get eggs or if there is any mating going on.

  4. All I see is a male in the photos that looks like he's lagging in development. I have a Barred Rock male like that. Oh and a little Mille Fleur D'Uccle cross that is also like that. He is 20 weeks and no saddle or hackle feathers, but his colouring alone is male.

    1. When I looked at the photos I thought male too. Does he crow?

      Even if he is not a he/she, this is very educational! Never heard of such a thing.

    2. Yes - I was thinking male for a while, but upon really studying this bird (not too hard as it is so friendly) I really do think it is a gynandromorph. It does not spar with the other birds and the older roosters don't seem to mind its presence whereas they chase off other young cockerels. I think the reaction of the other flock members to it is very telling - my older boys will gently establish their dominance with young male chicks before I even know those chicks are male. The roos just treat this one more like they do a guinea. They accept it but they don't seem to treat it as a gender specific bird.

      Time will tell and I will make updates. It certainly could simply be a developmental delay... but this would be the first time I have ever seen a bird develop identifiable, longer sickle feathers (only on one side) before getting at least a few sprouts of hackle or saddle feathers.

      We shall see!

  5. Very interesting story. I cant wait to see how h/she develops :)

  6. What is the breed of chicken? Fascinating

    1. Roberta - They are Swedish Flower Hens (even if they are roosters... or confused... )

  7. Any updates to this story? How did he/she/it turn out as an adult?

    1. Sadly s/he/it didn't live very long. It suffered a stroke - likely related to its oddities, and died soon after. :'(

  8. Replies
    1. No - it never laid and never crowed, but it was one of the sweetest chickens I ever had.

  9. I have a RIR bantam that, I'm so confused on as if it's a Roo or Hen. It has a Hen head, round saddle feathers, a Hen's tail, no Spurs,but had the marks as if it is growing Spurs, it crows,but digs in the nesting box, & it dances for other flock members,but won't do the deed wtih any of the Hen's. All my other Roos don't even challenge it at all in two days it will turn 7months we have named it Buddy,but still not sure what it is. Also the crow is very muffled & sounds choked out compared to my other Roos they have a true roo crow that is loud.

    1. Very interesting! Developmental flaws pop up all the time, and it is always fascinating to own and observe a chicken like this!

  10. We have a young crested silky who’s pen mate died of prolapse recently. They’re not even 1 yo. This white one is the only bird in the pen so when it started crowing we called rooster.. now it lays eggs AND crows.! WTF..? From Australia..

    1. LOL! It is not unheard of for a hen to crow if there is no rooster about. I have a Serama hen who will crow if taken away from her mate. She began this behavior when she was separated from the other birds whilst broody and crowed to her chicks all day.
      Odd but true!


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