Proponents of justice for animals often argue that non-human animals have an interest in liberty. Furthermore, they usually claim that this animal interest in liberty is intrinsic rather than instrumental; that is to say, liberty is regarded to be good for animals in itself, irrespective of its contribution to the achievement of other goods, such as pleasure. For this reason they argue that legislating to improve welfare standards in zoos, circuses, laboratories and agriculture is inadequate. Instead, they claim that such practices are analogous to human slavery, necessarily harmful, and must be abolished. In this paper I refute this assertion and claim that for most animals, their interest in liberty can only ever be instrumental. In doing...