Olsson, I. A. S., Dahlborn, K. 2002. Improving housing conditions for laboratory mice: A review of 'environmental enrichment'. Laboratory Animals 36, 243-270.

We have reviewed 40 studies carried out between 1987 and 2000, in which preferences as well as the effect of housing modifications have been studied. Mice will work for access to nesting material and make use of this material to make nests in which they rest. They prefer a more complex cage to the standard cage and will also work for access to cages with shelter and raised platforms.