Replies

“In the book Incognito by David Eagelman, the author discusses the strange nature of chicken sexing. This is the valuable process of separating female and male chicks as soon as possible, because each sex has different diets and endgames (most males are just destroyed). The mystery is that when you look at the vent in the chick’s rear, some people just know which are female. It is impossible to articulate, so the Japanese figured out how to teach this inarticulable knowledge. The student would pick up a chick, examine its rear, and toss it into a bin. The master would then say ‘yes’ or ‘no’ based on his generally correct observation. After a few weeks, the student’s brain was trained to masterful levels.”

“After thousands of years of assuming that hatchlings were physiologically indistinguishable, the Japanese determined in the 1920s that chicken sexing could, in fact, be taught. The then-new Zen-Nippon Chick Sexing School did just that. It offered intensive two-year courses on how to discern pullets (female) from cockerels (male). By 1934, it had trained over 1,400 sexers, turning Japan into the guardian of what became the poultry industry’s rarest, weirdest, and most important skill.”
“The central pedagogical aspect of sexing was and remains quick repetition over a focused period of time. The sexer must become proficient at immediately and unthinkingly recognizing the chickens’ vent shapes, of which there are hundreds of slight variations. With intense exposure to chick genitalia (and lots of perished chicks, as it’s common to squeeze them too tightly when trying to puff out their vents), Japanese students were consistently able to internalize pattern recognition and intuit rather than consciously identify the markers determining sex. Some achieved accuracy rates that were close to perfect.”

Looks to be intuitive depending on the master’s training level. Picking the arrows out of the air the Zen way.