Difficulties in evaluating animal welfare

Everyone is familiar with the scene: a parent calls in frustration to a child - Didn't you hear me calling you to come in?

There is uncertainty about whether:

• The child heard and chose not to respond and return (perhaps because it wanted to stay outside, or because it was frightened to go in);
  

• The child heard but could not return (perhaps because it was lost or injured);
  
• The child did not hear its parent calling;
  or
  
• The child heard but did not understand.
  

Interpreting human behaviour can be difficult. Inevitably, it is even harder to interpret the behaviour of other animals correctly. At least a parent can ask and receive a reply from a child, whether or not the reply is accurate or believed. But it is clearly futile for a vet to ask a fish to "Tell me what you want to do" or ask "Why do you feel like this?"

Knowing what different types of animal, and different individual animals, need in order to experience good welfare is not straightforward. It may be reasonably easy to recognise overt cruelty to animals that can reasonably be expected to induce pain and distress, for example, beating or starvation. It is much harder to recognise distress that may arise from an animal's inability to do something that it would otherwise do, for example nest building in the case of a caged bird.

Part of understanding what contributes to animal welfare involves evaluating the extent to which events which humans would find unpleasant, painful or distressing are experienced in the same way by other animals. We also need to be able to identify events that are distressing to other species even though they seem harmless to us. In other words, we need to adopt approaches for assessing animal welfare that are animal-centred, rather than human-centred.

It cannot be assumed that any single environmental or other factor will always be associated with a particular level of stress. The level of stress caused may differ in different animals, in different breeds and in different individuals.

We need to consider:

• Factors that cause distress e.g. acute and chronic pain, fear and deprivation, including boredom.
• Positive factors that improve well-being, including an animal’s ability to avoid distressing conditions.

Good welfare is more than simply an absence of pain, and it is intimately related to good health. It is reasonable to expect that welfare includes both physical health and mental "well-being". It is difficult/impossible to define an animal's subjective feelings, and so in this case mental well-being may equate more with an absence of stress than human concepts of happiness.

Animals are able to detect and respond to environmental factors such as temperature and light, but then so are plants and bacteria. Such behavioural responses can also be seen in computers and robot sensors. A key question in animal welfare is whether nonhuman animals are capable of conscious perceptions such as self-recognition, social communication, deceit and empathy. There is evidence of such behaviours in higher primates. If they were also to exist in animals such as sheep and pigs, there would be an even greater imperative to ensure high levels of welfare and to afford animals the appropriate protection.