Abstract Concern for animal well-being is increasing in technologically advanced societies that practise a strong respect for human liberty and have available a broad selection of affordable food. The predominant philosophical position of animal welfarists is that the capacity of animals' sentience, rather than species-affiliation, should serve as the guiding principle for human treatment of animals. In several Western countries, serious pressure enforced by law has required animal agriculture industries to alter or discontinue some systems of production in an attempt to improve the well-being of farm animals. It is important that the admirable goal of improving animal well-being is achieved in a methodical way to prevent serious, far-reaching errors affecting farmers, farm animals and society at large. A necessary prerequisite for this goal is a reliable definition of characteristics that pertain to an animal's quality of life. In this paper, it is proposed that quality of life is positively correlated with satisfaction of animal needs, comprised of life-, health- and comfort-sustaining needs. An objective assessment of quality of life should encompass all three categories of needs. A realistic parameter proposed to serve this purpose is longevity. The prime responsibility for the well-being of farm animals should be assigned to the professional associations of producers. To be effective, such self-administered responsibility would necessitate legislation specifically designed for the purpose.