Animal agriculture sustainability is being challenged by a rapidly increasing global human population, environmental pressures such as climate change, and a push toward reducing or eliminating antibiotic use. As a result, livestock producers are tasked with producing more animal products with less inputs and technologies while ensuring that appropriate animal welfare standards are maintained. The belief that distress should be limited for livestock to improve welfare is widely accepted by producers, scientists, and the public, and as such, farm animal welfare is an important societal issue. However, the correct way to assess the welfare state of livestock is often debated and using sound science to define what constitutes “good” animal welfare is a key component of developing animal husbandry practices and mitigation strategies to improve animal welfare while maintaining economic sustainability. The study of animal welfare is unique in that it often incorporates multiple scientific disciplines (i.e., stress physiology, behavior, immunology, nutrition) to evaluate the impact of various stressors on animal welfare and understand the interactions between differing biological systems under stressful conditions. Therefore, a multidisciplinary assessment of livestock welfare allows scientists to determine the relationships between animal behavior and physiology that can affect welfare states and ultimately influence animal performance and production efficiency.