Introducing Octopussy... My gender bender

[dunnmom]

This is my 2 yr. old BO, Octopussy. As you can see she has male physical traits. Large comb and wattles (doubled in size over 1 yr.), a fairly large spur on one leg, and she has an upright rooster-like stance. Her legs are thicker than her same breed sisters, and her body is broader, bigger, heavier. Her coloring is more brilliant also.

Her tail is beginning to curve, and she's growing longer saddle feathers. She has not stopped laying eggs yet, but I know that she might at some point, due to excess androgens. Ours is a roo-less flock, and I've heard this can happen, but I had no idea it would happen in mine. I plan to keep her as long as she does not begin crowing, because she's gorgeous and sweet.

I just learned that what could be happening to her is called gynandromorphism, and there are 2 main types, bilateral and mosaic. There are a number of different causes for such a hormonal imbalance. The odds of having such a hen is about 1 in 10,000, according to research, so that makes her pretty special IMO.

 

[dunnmom]

By the way, if anyone else has a gynandromorph hen, I'd love it if you'd post a picture of her down here in the comments.

 

[Birdsong 82]

Wow! Does it cause her any problems? Never heard of that. Does make her special

 

[pennyJo1960]

did find this I had heard of it not seen it
Half-male, half-female fowl explain sex determination.

Janet Fang

Hermaphrohen? 'Sam' is half male, half female.The Roslin Institute at the University of Edinburgh

A study of sexually scrambled chickens suggests that sex in birds is determined in a radically different way from that in mammals.

Researchers studied three chickens that appeared to be literally half-male and half-female, and found that nearly every cell in their bodies — from wattle to toe — has an inherent sex identity. This cell-by-cell sex orientation contrasts sharply with the situation in mammals, in which organism-wide sex identity is established through hormones.

The confused fowl have upended a century-old rule, established for vertebrates, that all cells in an embryo start off sexually indifferent and remain so until a sex-determining gene directs the development of gonads into either ovaries or testes. The work appears in today's Nature, and may trigger a rethink of the evolution of sex determination1.

Clucking confusing

Researchers were first alerted to the chickens by an employee in the poultry industry who spotted the unusual birds while visiting farms. A team of scientists eventually obtained three of the animals, which are known as gynandromorphs. The 'cockerel' side of these birds has white feathers, large wattles and breast muscles, whereas the smaller 'hen' side has characteristic dark colouring.

One gynandromorph was named Sam, for Samantha on the right and Samuel on the left. Like the other gynandromorphs, Sam was infertile and a bit confused. It seemed to think it was male, says Michael Clinton, a developmental biologist at the University of Edinburgh in Midlothian, UK who led the study. "But when we put it in with a couple of females I don't think they were too sure.


It's chromosomes, not hormones, that guide chickens' sexual development.Roslin Inst./Uni. Edinburgh

Gynandromorphs are striking because nothing like them has been seen in mammals. In almost all mammals, including humans, embryonic cells are initially sexually indistinguishable. During development, genetic factors trigger the formation of male or female gonads according to an animal's combination of sex chromosomes (XY for males and XX for females). The gonads then secrete hormones that direct other cells to develop as a certain sex.

"We assumed that sex determination in birds would follow the mammal pattern," Clinton says. Accordingly, the researchers thought that one side of the gynandromorphs would be a normal female (or male) and that the other side would have a some kind of chromosomal anomaly.

Instead, they found the chickens to be almost perfectly split between male and female. The hen half was, for the most part, made up of normal female cells with female chromosomes, whereas the cockerel side contained mostly normal male cells with male chromosomes. Because both sides were exposed to exactly the same hormones, the team realized that the cells must respond according to their own chromosomal complement rather than taking orders from the gonads.

Scrambled eggs

To test their hypothesis, the researchers created living embryos with chimaeric gonads by placing female cells in male tissue and vice versa. They found that female donor cells embedded in male cells didn't assume male functions. Similarly, male donor cells in an ovary-inducing environment didn't take on female roles. The team concluded that the cells couldn't switch sexual roles and that their orientation was fixed before they arrived.

Clinton says the work shows that chickens have a fundamentally different way of determining their sex from mammals: "Hormones do play some role, but nowhere near the extent seen in mammals." He suspects that the same rules apply to other species of bird, although gynandromorphs probably go unnoticed much of the time because the differences between the sexes aren't as pronounced.

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Combined with work on songbirds, this study strongly suggests that birds follow a different developmental pattern from mammals, agrees behavioural neuroscientist Juli Wade at Michigan State University in East Lansing who works on sexual differentiation in the songs of zebra finches2.

Birds aren't the only exception to the rule. The mammal model also fails with some marsupials and invertebrates like fruitflies. "The problem is, once people develop a hard and fast rule, it becomes the only game in town," Clinton says. Sam's "tubes and plumbing" would suggest there is no rule for all vertebrates.

Next, the researchers want to show by just how much these sex differences precede sex-hormone influences. "We believe the cells know they are male or female at fertilization," Clinton says.

 

[dunnmom]

Wow! Does it cause her any problems? Never heard of that. Does make her special

It doesn't seem to cause her problems, but it might have an effect on her internally. Like when a woman has polycystic ovary syndrome, it can cause her androgens to rise, she may have blood sugar issues, and infertility that can't be seen with the eye. It may or may not impact her health. It may depend on why it's happening in the first place.

 

[dunnmom]

If this is what's happening with her, it has to be mosaic gynandromorphism, because bilateral is present at birth. Mosaic can develop later due to tumors, cysts, things of that nature. I wonder how much more she might look like a roo next year. I haven't taken her to a vet as she doesn't seem to be in any pain or sick.

 

[hwar]

When I was a child, our flock lost its beloved rooster and the dominant hen (a RIR) developed masculine comb, tail feathers, etc. At the time, we thought it was because of the rooster’s absence, but it seems that it was probably more complex than that! We got another rooster and her “change” didn’t progress any further. She resumed her role as dominant hen. I don’t know if it affected her laying or not. I wish I had pictures, but this was back before digitial cameras!

 

[dunnmom]

When I was a child, our flock lost its beloved rooster and the dominant hen (a RIR) developed masculine comb, tail feathers, etc. At the time, we thought it was because of the rooster’s absence, but it seems that it was probably more complex than that! We got another rooster and her “change” didn’t progress any further. She resumed her role as dominant hen. I don’t know if it affected her laying or not. I wish I had pictures, but this was back before digitial cameras!

That's a cool memory! It seems there hasn't been much research on this occurrence in chickens. We may never know the full scope of how or why things like this happen in nature, but we'll always try to figure it out, because that's human nature.

 

[beccaWA]

How bizarre! TY for the info on chicken gender and how it works. BTW, your chickens appear to have scaly leg mites. Treat with Ivermectin (usually from a vet) and it will treat that, as well as almost all other internal/external parasites, except for tape worm.

 

[dunnmom]

How bizarre! TY for the info on chicken gender and how it works. BTW, your chickens appear to have scaly leg mites. Treat with Ivermectin (usually from a vet) and it will treat that, as well as almost all other internal/external parasites, except for tape worm.

Yes, she does. She's the only one with raised scales. The others don't seem to have it, but they probably do. I plan on doing an all flock mite/lice dip tomorrow when I have help. I removed everyone's leg bands last night, too as I noticed hers were too tight on her legs. My husband won't let me use chemicals on our chickens, so I'll be using neem oil, which is said to work well. We shall find out.