Despite the many scientific objections that have been raise to it, 'natural behaviour' is widely used as an indication of good welfare by the food industry. The supposed link between welfare and natural behaviour derives, however, from a now outdated view of animals becoming frustrated if they cannot perform their natural instinctive behaviour. On the 60th anniversary of its publication, Niko Tinbergens' Four Questions framework is used to show why there is no necessary link between natural behaviour and welfare and why, therefore, reliance on natural behaviour in commercial farming may not result in the claimed improvements in welfare. Used on its own without supporting evidence, 'natural behaviour' lacks the most essential criterion for good welfare-whether it matters to the animals themselves. There are now a number of well-established methods for demonstrating what animals value, including choice tests and, particularly, what animals will work and pay a cost to obtain. Some of the evidence on what animals value is already available in published papers but some will require collaborative research between scientists and commercial farming to find practical and commercially viable ways of providing animals with what they value.
Keywords: 4 questions; Tinbergen; farm animal welfare; natural behaviour; rewards.