《农桑辑要·典训·经史法言》
羊只的足数满一千；沼泽水草丰茂地带，猪满千只足；韦昭说： 千只足是二百五十头。 
千足羊；泽中千足彘；韦昭曰：二百五十头。
Full a thousand hoofs of sheep; and in the marshy and grassy areas, full a thousand hoofs of pigs. Wei Zhao said: The thousand hoofs are two hundred and fifty.