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November 7, 2019 5 mins

In cases of spontaneous sex reversal, an animal born male can become female, or vice versa, due to genetic or hormonal changes. Learn the story of how one hen became a rooster in this episode of BrainStuff. 

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Speaker 1 (00:01):
Welcome to brain Stuff production of iHeart Radio. Hey brain Stuff.
Lauren bog obamb Here. Miss Lucille was a sweet pullet,
which is a term for a young hen who had
found a cozy home in a backyard chicken coop in
Powder Springs, Georgia. Initially, things appeared to be status quo
with the young exchequer leg horn cross. After observing her

(00:23):
for a time, however, her owner, who wished to remain anonymous,
noticed Miss Lucille was growing a comb. Although both sexes
of the breed can have them. Her owner's instincts told
her that perhaps something wasn't quite standard, so she sought
the help of a local farmer. The owner recalls the
farmer did all the checks to confirm Miss Lucille was
a miss. She had no saddle feathers, which are pointy

(00:46):
feathers at the base of the tail, no aggression, didn't
jump or react in the presence of other hens or roosters,
and when she was laid back in the farmer's hand,
she stuck her legs straight out and just laid there.
All our old timers tricks to identifying roosters, since there's
no definitive way to tell until they mount another chicken
or crow aside from lab testing, so Miss Lucille had

(01:08):
failed the rooster test. However, later on the owner arrived
home to a mess of feathers in the backyard, an
unusual event because hens don't usually molt until around eighteen
months of age. The owner said she began acting more temperamental,
but I attributed that to her molting, as it can
be quite uncomfortable for chickens. I was worried about her health.

(01:28):
Although strange things were certainly a foot in Miss Lucille's world,
none of them were health threatening. When her feathers grew back,
they were saddle feathers like those found on roosters. Her
hackles and tail feathers had also undergone some major changes.
Her owner said she went from being your typical hen
to a rooster with beautiful long tail feathers and pointy hackles.

(01:49):
Her gait changed, and she was definitely at the top
of the pecking order. Further consultation advised a weight and
see approach. One farmer told the owner just because she
now looked like a rooster didn't mean she was one.
I needed to wait until she crowed or mounted one
of the hens. Miss Lucille's comb continued growing, but she

(02:09):
also became more mellow and friendly. Her owner said for
every indicator that she might still be as she, there
was another for her being a he. Finally, irrefutable proof
came at around five months of age. The rooster literally crowed.
Her owner said. Every day the crow grew louder and stronger.
It was official that Miss Lucille was now Mr Lucille,

(02:31):
and to his credit, he assumed the role wonderfully. If
the girls were low on water, he'd crow, would let
me know to get it on. He'd lead the charge
up to roost at night. He'd wake us up with
his song early each morning. So how does a hen
become a rooster? Spontaneous sex reversal, such as in the
case of Mr Lucille, is extremely rare. A study out

(02:52):
of Bangladesh found that only twenty eight of three thousand
hens monitored underwent reversal. The jury is still out on
exactly why this phenomenon occurs, but there are some prevailing theories.
According to Drew Benson, Assistant professor of poultry science at
the University of Georgia. Benson said via email, current evidence
shows that sexual differentiation in birds is a mix of

(03:13):
direct genetic and hormonal mechanisms. The right ovary and overduct
regress during embryonic development, leaving the hand with only one
functional ovary, the left one. Should the left ovary be
removed or become dysfunctional due to disease, the regressed right
ovary may form an ovotestis, he explained, but let's break

(03:34):
that down a little. Most instances of spontaneous sex reversal
in birds, such as Mr. Lucile's, are believed to be
connected to alterations in sex steroid hormone action, such as estrogen.
The hypothesis is that estrogen activity suppresses development of the
right gonad, but when the ovary fails to secrete estrogen,
the tissue in the undeveloped right gonad is then changed

(03:56):
to an ovotestis, which is a testis like structure that
will again to secrete androgens and give the female bird
more physical characteristics usually seen in males. Benson noted that
the lack of estrogen will change the bird's plumage, and
the increased testosterone causes the crowing and growth of head
ornaments like the wattle and comb. Scientists aren't sure why

(04:18):
this happens. Benson said that it's pretty common for ovarian
disease to cause dysfunction of the ovaries, yet spontaneous sex
reversal is much less common. He said, you couldn't simply
remove an ovary from a hen and generate a spontaneous
sex reversal. The exact mechanism underlying Avian sex determination has
yet to be resolved. So what's a hen turned roosters

(04:40):
owner to do? Benson said, embrace the fact that you
have a rare chicken. The newly changed chicken is no
longer going to produce eggs, so you would need to
get a new hen if you wanted egg production. Our
anonymous owner wound up having to farm Mr Lucile out
to another rooster lover once the crowing got out of control.
She said, we have a subdivision behind our house, and

(05:01):
although we are fortunate enough to be able to have
roosters on our property, we didn't feel it was the
neighborly thing to do. While I miss him, I don't
miss the early morning wake up call, and I'm happy
he's where he can do his thing freely. Today's episode
was written by Alia Hoyt. And produced by Tyler Clang.

(05:22):
Brain Stuff is a production of iHeart Radio's How Stuff Works.
For more in this and lots of other Croworthy topics,
visit our home planet, how stuff Works dot com. And
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