Batchelor, G. R. 1991. Environment enrichment for the laboratory pig. Animal Technology 42, 185-189.

This brief paper attempts to illustrate the simple ideas that can be used to enhance the environment of the laboratory pig. ... It does not describe the behaviour of the pig in any detail but suggests that with a little time and effort, and in our case at no cost, the environment of the laboratory pig can be made more stimulating, resulting in animals that have an increased behavioural repertoire, are largely stress-free and are a constant pleasure to work with. Straw has important recreational value for pigs. A strong argument against straw is the potential problem of straw clogging drainage systems; a trap on the drain can readily avoid this problem.