This chapter delves into the various physiological measures that can be used to gauge the thriving status of animals, emphasising the importance of routine veterinary examinations, body condition scoring, and quality of life assessments. It discusses the integration of these measures into a comprehensive animal welfare strategy, ensuring that each animal receives the necessary care tailored to its specific physiological needs. The chapter also highlights the implications of these practices for improving animal welfare, advocating for a science-based approach to animal care that aligns with the latest research and ethical standards in the field. This abstract provides a concise overview of the chapter’s focus on the critical role of physiological health in the overall welfare of animals, underscoring the necessity for ongoing research and adaptive care practices to enhance the quality of life for animals in human care.