Measuring preferences and the strength of preferences.

In this review, it is argued that welfare concerns what animals feel. Preference tests give a good first indication of how animals feel and are therefore extremely valuable in animal welfare studies. Methods of overcoming the shortcomings of preference tests are discussed. In order that the results from preference tests be interpreted properly, they should be followed up with appropriate tests to measure the strength of preference. Examples of research in this area that have focused on poultry are given.