I am grateful to Camilla Ryberg for diligent research assistance; to John D. Lawrence for kindly providing data on profits in swine production; to Rod Preece, Joy Mench and Suzanne Millman for allowing me to repeat here some ideas that we developed in our joint publications; and to many colleagues at FAO and the University of British Columbia Animal Welfare Program for helpful discussion. Some material in this paper has been adapted from my contribution to the forthcoming book A communion of subjects: animals in religion and ethics, edited by Paul Waldau and Kimberley Patton, Columbia University Press. Preparation of the paper was made possible by the Animal Production and Health Division of FAO, and by the University of British Columbia Animal Welfare Program, which is supported by the Natural Sciences and Engineering Research Council of Canada and many other sponsors listed at http://www.landfood.ubc. ca/animalwelfare/.
David Fraser spent six months at FAO in 2004 - 05 as a Visiting Scientist, working with the Organization on questions related to animal welfare. This essay was written during his time at FAO.