Over the past 60 years, our understanding of the livestock animals under our care, and our subsequent treatment of them, has progressed from the days of Ruth Harrison's Animal Machines, a time when farmed chickens were excluded from legal protections created for birds. This book takes us through the introduction of considerations of sentience, the ethical matrix and animal autonomy, the Five Freedoms, welfare quality assurance schemes on farms, and our current concerns of the sustainability of the animal agriculture industry.Combining and reflecting on the earlier works of John Webster, an established animal welfare expert who coined the Five Freedoms concept, this book reinspects the extended journey of animal welfare science.