Due to varying demands in the poultry processing industry, chickens have to be sorted by sex as soon as possible after birth to fit in with different markets. /VCG Photo

In China, a proficient chicken sexer is paid over 10,000 yuan (some 1,453 US dollars) per month, but few are aware of this highly-skilled "dirty job" which requires professional training. /VCG Photo

Ms. Ren, who works at a hatchery in northwest China’s Shaanxi Province, is capable of sorting two newborn chickens within just four seconds. She says 20 years of experience have ensured her efficiency and accuracy. /VCG Photo

According to Mr. Li, the hatchery boss, well trained chicken sexers are often lured overseas since they are in great demand across the world. /VCG Photo