So, mapping the geographical distribution of poultry and pig production systems is likely to
be extremely important in understanding the environmental, social and health impacts of
intensification of livestock production. Several previous studies, have developed methods to
map different species of livestock [30–33], and existing maps of the global livestock distribution
have recently been revised, using new methodologies and data [34]. However, very little work
has yet been done to separate extensive from intensive production in distribution maps.