In Britain we’ve been regulating animal welfare since the slightly unfortunately named “Humanity Dick” (real name Richard Martin) got the Cruel and Improper treatment of cattle bill passed in 1822.
But the idea of animal welfare and animal rights remains a hugely controversial one. In 1975 philosopher Peter Singer argued in Animal Liberation that the boundary between humans and animals is completely arbitrary. Although campaign groups such as the RSPCA (founded in the 19th century) had long been trying to improve animal welfare, Singer’s book arguably kicked off the modern animal rights movement.
The result of much campaigning and pressure has been a number of regulations. In 1998 the European commission passed a directive which stated that all animals kept for farming purposes must reflect the “five freedoms” - freedom from hunger and thirst; discomfort; pain; injury and disease; fear and distress, and freedom to express normal behaviour. In 2009 the Lisbon treaty recognised animals as sentient beings.
In 2012 an international group of scientists met at Cambridge University to sign (in the presences of Stephen Hawking) the Cambridge Declaration on Consciousness, which declared that “the weight of evidence indicates that humans are not unique in possessing the neurological substrates that generate consciousness. Non-human animals, including all mammals and birds, and many other creatures including octopuses, also possess these neurological substrates”.
Globally OIE, the World Organisation for Animal Health, has a number of standards.