Spontaneous Sex Reversal in Chickens

A brief explanation of spontaneous sex reversal in chickens, including frequently asked questions.

What is Spontaneous Sex Reversal?​

Spontaneous Sex reversal is an uncommon phenomenon where a female chicken develops male characteristics.

Why does it Happen?​

Female chickens have two ovaries. The one on the left side is the only one that develops in healthy birds. The one on the right doesn’t function. However, if it is damaged it can develop into an ovotestis, which contains male and female tissues and releases male and female hormones. The male hormones cause the hen to develop male characteristics such as spurs, pointed feathers, and larger combs and waddles. The hen may even start to crow!

F-A-Q​

Q: Is a hen who has gone through spontaneous sex reversal considered a male or female bird?
A: It is still a female, just with the secondary characteristics of a male. They are genotypically females and phenotypically males.

Q: Can a rooster turn into a hen in this same fashion?
A: No, this has not been documented.

Q: Is spontaneous sex reversal permanent.
A: Yes

Q: Can chickens who go through this process reproduce?
A: There have been reports of semen production, but rarely do these birds actually reproduce.

My Experience​

I have owned a Barred Rock hen for 10 years. One day I noticed she was developing longer feathers in the tail and hackles. She must have suffered damage to her ovaries through a disease because she has experienced spontaneous sex reversal. The only male characteristics I have seen in her are the longer feathers, which you can see in the below picture.
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Further Reading​

Let’s talk about Spontaneous Sex Reversal!

The Life and Times of Betty the Transgender Chicken

Credits

When "she" becomes "he" - spontaneous sex reversal in chickens

SEX REVERSAL IN CHICKENS – Small and backyard poultry
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GodLovesU
Hi, I’m Shelby! I am a teenage Christian girl and raise button quail, coturnix quail, and chickens. I enjoy spending free time on BYC to help and educate people. I hope you enjoy reading my articles! If you have any suggestions, please leave a comment! Have a blessed day!

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