Sheep have been reared by the Tzotzil Indians in Highland Chiapas in southern Mexico for over 450 years. Following the failure of various government programmes intended to raise productivity, this study tried a new approach to improving sheep husbandry management. The researchers followed the herds, making observations and interviewing the shepherdesses individually. Previous programmes had failed because of a lack of understanding of the culture of the Tzotzil Indians, in which sheep are viewed as sacred animals. As a result, many of the recommendations were not only inappropriate, but opposed to Tzotzil culture. The study found that the shepherdesses have designed and perfected a management system, based on a blend of Spanish and traditional practices, that has proved very effective.