Animal welfare has become a growing concern affecting acceptability of agricultural systems in many countries around the world. An earlier Judeo-Christian interpretation of the Bible (1982) that dominion over animals meant that any degree of exploitation was acceptable has changed for most people to mean that each person has responsibility for animal welfare. This view was evident in some ancient Greek writings and has parallels in Islamic teaching. A minority view of Christians, which is a widespread view of Jains, Buddhists and many Hindus, is that animals should not be used by humans as food or for other purposes. The commonest philosophical positions now, concerning how animals should be treated, are a blend of deontological and utilitarian approaches. Most people think that extremes of poor welfare in animals are unacceptable and that those who keep animals should strive for good welfare. Hence animal welfare science, which allows the evaluation of welfare, has developed rapidly.