'Animal welfare' is the desire to prevent unnecessary animal suffering (that is, whilst not categorically opposed to the use of animals, wanting to ensure a good quality of life and humane death)
Source: www.worldanimal.net
The European Commission has defined the so-called "Five Freedoms" to define ideal states of animal welfare:
1) Freedom from hunger and thirst - access to fresh water and a diet for full health and vigour;
2) Freedom from discomfort – an appropriate environment with shelter and comfortable rest areas;
3) Freedom from pain, injury and disease – prevention or rapid treatment;
4) Freedom to express normal behaviour – adequate space and facilities, company of the animal’s own kind;
5) Freedom from fear and distress – conditions and treatment which avoid mental suffering
Source: European Commission