| factors affecting mortality of crossbred and exotic chickens kept under backyard systems in yucatan, mexico. | chicken mortality was studied in 24 randomly selected smallholder flocks in one village in yucatan, mexico between july and december 1993. each family received a package of 10 to 12 chicks of 3 weeks of age. approximately half of the chicks were purebred and the remainder were crosses produced by mating exotic with local breeds. all smallholders were visited twice a week. feeding and management (except vaccination and medication) were left to smallholders. data were processed by chi-square, mant ... | 1997 | 9316231 |