Heard in the shop:
Her, picking up the book, and leafing through the photo section: "Ew, I'm not reading this, it's pornographic!"
Him: "Only if you're a chicken."
Sexing Day-Old Chicks by W. P. Blount is a rather rare volume, it appears. Or at least original editions are: there are currently no copies of either the first or second editions available online anywhere. It is however very much available as a print on demand title, which suggests that what Mr Blount first wrote back in the 1940s still has a practical use, so good for him (his other books include Poultry Ailments and its blockbuster sequel Rabbits' Ailments).
Sniggering aside, sexing chicks is a very particular skill, which is still done by humans, by hand, at a rate of 350 per hour or more per sexer. Without getting into too much detail (as W. P.'s book does, graphically), you have to pick them up, and have a look at their nether regions, where a tiny, tiny difference, barely visible to the eye, makes all the difference, as it were. (And if you don't know what then happens to the no-eggs-so-therefore-no-use male chicks, it's best not to ask.)
Apparently sushi chefs are taught that when making sushi, you should not squeeze the fish, 'but hold it firmly like a day-old chick'. Whether that makes chick-sexing and sushi-making interchangeable skills I don't know, but it would be a good episode of one of those job-swap reality shows, that's for sure.
The only thing harder than learning how to sex chicks is coming up with a way to accurately teach people how to sex chicks. Withnail Books' Psychology Correspondent writes:
W. P.'s book has 9 chapters of words, plus a chicken-porn photo insert which I will not delve into here, barring the first picture: an informative piece on how the sexer's table should be arranged. I'd like to think that the stern-looking chap at the table is W. P. himself. As he writes in his Introduction: "There is little doubt that chick sexing has come to stay."