Cui Yongshun, 49, is one of the "collectors" who roam from village to village, seeking animals to buy for Qimeisi Pork. Since January, he said, it has become increasingly difficult to find satisfying pigs of 100 kilograms.

The temperature was as high as 33 degrees C on Monday in Zibo, Shandong, and Cui`s only friend was a towel to wipe away his perspiration. That morning, Cui had just brought in 18 pigs on a truck designed for 50.

At lunch, he met with another collector, Cao, and they talked about their difficulties and how to find a new farm to buy from.

"After collecting pigs for the past five years, I know every single pig farmer in about 10 villages nearby," Cui said. "But currently, most pigs are 75 to 80 kg."

That means they would produce only about 50 kg of pork, compared with 80 kg from a 100-kg pig. But after lunch, Cui stepped onto the truck without hesitation. More pigs mean more pay from the factory.

Meanwhile, his 18 pigs had been corralled in the factory pigpen, which can hold 1,000. At 1 pm, workers hung one of the pigs up by its hind legs, and the slaughtering process began.

China Daily