Chicken Sexing

While reading Moonwalking with Einstein, by Joshua Foer, I learned about chicken sexing, a real-world issue I never even knew about.

As with most higher order animal species in the world, about 50% of all individuals are born male and the other female.

Female chickens are highly useful. We eat them as “chicken” and they lay the eggs we use for our omelettes. Male chickens are called cockerel or cocks when they are grown up. They crow in barnyards in the morning, they fertilize chickens, and they have pretty much no other use. But in chicken hatcheries they are treated like a byproduct, similar to sawdust in a furniture factory. Their meat is stringy, they don’t lay eggs, and they mess with the chickens and cause them stress. Not much different from human males.

In the global chicken industries, female chickens are chosen for long, productive lives. Males are eliminated as fast as possible. The problem is that it is virtually impossible to determine the sex of a chicken until it’s about four to six weeks old. Until then they are all identical yellow fluff balls. To get to six weeks, all the males have to be fed and housed at significant expense.

For millenia, this was a serious problem, driving up the overall cost of chickens and eggs. In the 1920s a group of Japanese veterinary scientists discovered a way to determine the sex of a chicken by examining the arrangements of folds, marks, bumps and spots just inside the cloaca of a one-day-old bird. This is completely unintelligible stuff for a uninitatated person. Eventually they revolutionized the global chicken industry and brought the cost of the product down signficantly by educating chicken sexers. The best were graduates of the two-year Zen-Nippon Chick Sexing School. Their standards were so rigorous that only 5 to 10 percent of students received accreditation. Supposedly it takes over 17,000 chickens before one starts being able to tell. Now, there is an elite profession of chicken sexers that can process between 1000 and 1700 birds an hour. The males go down the left chute. The females the right one.

Now you may wonder what happens to the male chicks after they go down the left chute.

I do not know, and I don’t want to know.

One thought on “Chicken Sexing

  1. Eric Petrie

    Just another strange fact about science. In this case, it adds to efficiency. In another case, it makes possible strange gender ratios in China and who knows where-else.

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