A farmer wanted to be able to tell which of his
baby chicks were boys and which were girls so he enlisted the aid of a
scientist. “Well!” said the scientist, “It’s really quite
easy! You simply scatter some crickets
in the coop. The boy chicks will only
eat boy crickets and the girl chicks will only eat girl crickets.”
“That’s great!”
said the farmer. “But how do you tell the boy crickets from the girl
crickets?”
“Why are you asking me about crickets?” the
scientist retorted. “I’m a chicken
expert!”
And for the bulk of history after the
domestication of chickens, sexing baby chicks wasn’t too far from that mark. The bad news is that baby chicks are pretty
much small, cute, fluffy, and indistinguishable, with their boy and girl parts mostly
inside their bodies and out of sight. The
good news is that for a long time, it really didn’t matter a whole lot.
Chicken husbandry back in the day went
something like this: In the spring, hens
would make a nest, lay eggs, and brood them.
The farm wife (and it was almost always women taking care of the
chickens) would risk the ire of the broody hen to collect some of the eggs and then
everybody got fried eggs. Other hens
either got left alone, or hid their nests in places where nobody could find
them. After about three weeks they would
show up with a string of peeping baby chicks behind them. These babies – maybe a couple dozen of them
on the typical farmstead—would follow their mom around, eat bugs and spilled
grain, and grow. By late summer the
pullets would look like pullets and would be laying their first little eggs
while the cockerels would look like cockerels and would be making some practice
runs at crowing. Then the cockerels
would start showing up on the dinner table.
The pullets would be kept over the winter and would become the broody
hens the next spring. Most likely before
their second winter, they would wind up in the stew pot since their egg
production would tail off the second year.
It was a pretty good system and there wasn’t a
lot of need to differentiate the baby hens from the baby roosters. Things began to change in the early part of
the 20th century with the advent of chicken breeds that were
specifically designed as meat birds.
Suddenly, the roosters of the egg-laying breeds had no purpose and
keeping them around until they started to crow was a waste of feed and
resources. Somebody needed to develop a
way to tell baby roosters from baby hens.
That
somebody was Professor Reginald Punnett a geneticist at the University of
Cambridge. Punnett developed the first
of a series of “autosexing” chicken breeds in the 1920’s. Autosexing baby roosters have different color
patterns from baby hens when they hatch.
Dr. Punnett exhibited the Cambar at the World Poultry Congress in 1930—the
world’s first autosexing chicken. While
the Cambar and subsequent autosexing breeds, the Gold, Silver, and Cream
Legbars were not particularly good egg or meat producers, everyone was sure
that autosexing breeds would ultimately revolutionize the poultry industry once
better egg and meat production was bred into their lines. As it turned out, everyone was wrong. Cambars and Legbars turned out to be a mere
sidebar in the history of the poultry industry due to a development that
occurred around the same time on the other side of the world.
In
1925, Dr. Kiyoshi Masui at Tokyo Imperial University reported on certain anatomical
differences he found between male and female chicks. This work eventually resulted in the scientific
paper “The Rudimentary Copulatory Organs of the Male Domestic Fowl and the
Difference of the Sexes of Chickens”.
The gist of the report, in laymen’s terms, was that to tell the
difference between little boy and little girl chicks, you just had to do what
you did with every other baby animal—pick them up, turn them upside down, and
look at their private parts. It was just
that the differences between boy and girl chicks were reeeaaallly subtle. While the report generated interest around
the world, the general consensus was that sexing baby chicks by this method
would never be commercially viable because the difference was so very subtle
that it would take too long to examine each chick.
It
was two Japanese poultrymen, Kojima and Sakajiyama, who turned Dr. Masui’s
discoveries into a practical application that soon became widespread on the
farms and in the hatcheries of Japan. A skilled
chicken sexer could sex baby chicks in rapid fashion with an accuracy of 95% or
greater.
What
do chicken sexers look for? Most baby
roosters will have an “eminence” that looks like a small pimple in the middle
of the lower rim of their vent. Most
baby hens will not. Please note that I
used the word “most” in both of the previous sentences. That’s because a certain percentage of both
hens and roosters will have confusing bits in their vents—not pimples but sort of tiny pimple-like things. Being able to sex
these chickens is very, very difficult, and both teaching and learning how to
discern all the subtleties is almost impossible. This knowledge can’t be transmitted through a
book, requires in-person tutoring, lots of practice, and is as much art as
science. Consequently, chicken sexers
are in high demand, and are paid well.
Interestingly enough, a large number of chicken sexers today, worldwide,
are Japanese.
While
vent sexing has revolutionized the poultry industry, it has not been good news
for roosters. Baby chicks are sexed
shortly after hatching, in a production line sort of setting (see a video of baby chick
sexing here) and immediately after being sexed the baby roosters are
euthanized, usually by being tossed into a grinder.
Hence, we catch sight
of the dark underbelly of modern poultry in all of its forms. Regardless, of whether we enjoy our chickens
through cracking open a dozen fresh pasture raised eggs, by digging into a box
of fast-food fried chicken, or by tending our backyard pet chickens, we are in
collusion with an industry that kills half of the baby chicks as soon as they
hatch because they’re roosters.
The good
news: There may be a way out of this
inhumane dilemma. In 2016, a German
scientist named Roberta Galli and her colleagues published a paper entitled “In Ovo Sexing of Domestic Chicken Eggs by
Raman Spectroscopy”, which describes a technique for determining the
sex of a chick while it is still in the egg and after a mere 3.5 days of
incubation. The procedure doesn’t
contact the chick embryo at all beyond the creation of a small hole in the
egg. A special light is beamed into the
hole and is then analyzed. A sexing accuracy
of 90% was obtained using this method. If
this technique becomes commercially viable, hatcheries could remove eggs containing male embryos four
days into incubation (it is generally accepted that chicks gain sensitivity
around day 7) and the need for killing male baby chicks would be
eliminated.
This promising technique has garnered attention from
around the world. PETA announced "Reports
that countless male chicks could potentially be spared the horrors of being
thrown into high-speed grinders…would be celebrated by animal campaigners…” The United Egg Producers, the egg industry
trade group in the US has pledged to eliminate the culling of day-old male
chicks by 2020 “or as soon as economically feasible alternatives are available.” Shortly after the scientific report was
published in 2016, Germany's food and agricultural minister, Christian Schmidt,
promoted having the new method operating nationwide by 2017
so Germany could be a "pioneer for better animal welfare in egg production
in Europe."
Over a year has passed since the initial scientific
paper and things have been fairly quiet about this new technique. It’s safe to say that nobody is using it
commercially. But Dr. Galli is quietly
continuing her research. In a paper
published in February, 2017, she reported on replacing pricey Raman analysis with
cheaper fluorescence and suggests that this cheaper methodology may make the
technique more appealing. She concludes
her paper with the hope and wish that “the availability of a cheap[er] and easier approach... might contribute to a broader diffusion of
optical sexing in the hatchery practice. On an international scale, development
of a practicable technique for in ovo sex determination has the potential to
contribute to the prevention of annual culling of 7 billion male layer hybrids,
whose female siblings produce the current global demand of about 68.3 million
tons of eggs per year.”
For chickens everywhere, and for the humanity of
chicken keeping, I hope that this new method of chicken sexing will be put in
place everywhere as soon as possible.
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