Batchelor, G. R. 1993. An enriched commune housing system for laboratory rats - a preliminary view. Animal Technology 44, 201-213.

I believe that rats housed in research laboratories in polypropylen boxes with a floor area of 1600 sqcm and a height of 20 cm are ethologically, physiologically and psychologically aberrant and cannot be considered as normal animals. An enriched group-housing system is described.