This paper discusses the scientific conception of animal welfare and its relationship to ethical concerns. It argues that current scientific definitions of animal welfare are insufficient to address the ethical issues surrounding the quality of life of animals. The paper outlines three major ethical concerns regarding animal welfare: (1) the natural living of animals, (2) the feeling well of animals, and (3) the functioning well of animals. It critiques various scientific conceptions of animal welfare that focus on only one of these concerns and proposes an integrative model that encompasses all three. The model suggests that animal welfare research should address three types of problems that may arise when an animal's adaptations do not fully correspond to the challenges posed by its environment. These problems include (1) when an animal's adaptations no longer serve a significant function, (2) when an animal faces challenges for which it has no corresponding adaptations, and (3) when an animal's adaptations are inadequate for the challenges it faces. The paper concludes that a scientific conception of animal welfare must reflect these ethical concerns to effectively address the quality of life of animals.This paper discusses the scientific conception of animal welfare and its relationship to ethical concerns. It argues that current scientific definitions of animal welfare are insufficient to address the ethical issues surrounding the quality of life of animals. The paper outlines three major ethical concerns regarding animal welfare: (1) the natural living of animals, (2) the feeling well of animals, and (3) the functioning well of animals. It critiques various scientific conceptions of animal welfare that focus on only one of these concerns and proposes an integrative model that encompasses all three. The model suggests that animal welfare research should address three types of problems that may arise when an animal's adaptations do not fully correspond to the challenges posed by its environment. These problems include (1) when an animal's adaptations no longer serve a significant function, (2) when an animal faces challenges for which it has no corresponding adaptations, and (3) when an animal's adaptations are inadequate for the challenges it faces. The paper concludes that a scientific conception of animal welfare must reflect these ethical concerns to effectively address the quality of life of animals.