The welfare of an animal includes its physical and mental state, and good animal welfare implies both fitness and a sense of well-being. Any animal kept by humans must, at least, be protected from unnecessary suffering.

An animal's welfare should be considered in terms of 'five freedoms'. These freedoms define ideal states rather than standards for acceptable welfare. They form a logical and comprehensive framework for analysis of welfare within any system together with the steps and compromises necessary to safeguard and improve welfare.

1. Freedom from Hunger and Thirst - by ready access to fresh water and a diet to maintain full health and vigour.
2. Freedom from Discomfort - by providing an appropriate environment including shelter and a comfortable resting area.
3. Freedom from Pain, Injury or Disease - by prevention or rapid diagnosis and treatment.
4. Freedom to Express Normal Behaviour - by providing sufficient space, proper facilities and company of the animal's own kind.
5. Freedom from Fear and Distress - by ensuring conditions and treatment which avoid mental suffering.

The Five Freedoms were first proposed in Britain in the 1960's, originating with an enquiry into the welfare of animals that were kept in intensive farming conditions during 1965 in the UK. The Farm Animal Welfare Council, established by the British government in the late 1970's to advise it on legislative and other changes for farm animals, subsequently affirmed the Five Freedoms. The Council was conservatively made up of individuals with connections to agriculture: farmers, animal farming company directors, veterinary surgeons and academics specialising in agriculture. Other bodies concerned with animal welfare have approved the Freedoms.

The following table illustrates how to assess an animal's welfare in terms of the Five Freedoms:

Irish legislation typically only steps in when an animal's life is 'not worth living', rather than borderline or poor quality of life. And even then it's very hard to get charges filed at all, let alone prosecutions followed through.