Understanding animal welfare.

In this chapter, we introduce some of the principal issues that have arisen in relation to scientific approaches to animal welfare, most of which are treated in more detail later in the book. Much of the apparent disagreement between people about animal welfare stems from mixing up scientific questions about the actual welfare of animals and ethical questions about how we ought to treat and care for animals. This chapter does not deal with these ethical questions but focuses on the science of animal welfare and on the different approaches taken in the past to understand what animal welfare is and how to assess it. We nevertheless put animal welfare in its social context by presenting a brief history and referring to some key events that have shaped the development of animal welfare science. We discuss the links between animal welfare and animal health, and the links between animal welfare and natural behaviour. Although these links seem selfevident, and the assessment of welfare based on these approaches often leads to the same conclusions, there are many considerations that are not usually taken into account. Examples include how difficult it is to define good health, or to compare the degree of suffering experienced by animals with different types of disease, illness and injury. Furthermore, even if behaviour has evolved because it contributes to the survival of animals under natural conditions, not all natural behaviour is desirable. Ultimately, we argue that as concern about the welfare of animals stems from the fact that they are sentient (capable of feelings), then feelings have to be a major part, perhaps the central part, of their welfare.