John Webster, MA, Vet MB, PhD, DVM (Hon), is a retired Professor of Animal Husbandry at the University of Bristol, Bristol, UK. He established the Bristol Unit for Study of Animal Welfare and Behavior and is a founding member of the UK Farm Animal Welfare Council (FAWC). Published as a part of the prestigious Wiley Blackwell - UFAW Animal Welfare series. UFAW, founded in 1926, is an internationally recognized, independent, scientific, and educational animal welfare charity. For full details of all titles available in the series, please visit our website at www.wiley.com/go/ufaw.