An investigation into the effects of solid or grid cage flooring on the welfare of laboratory rats (1995)

Manser, C. E., Morris, T. H., Broom, D. M.

Abstract

Preference testing revealed that rats chose to dwell on solid floors rather than grids, regardless of previous housing experience. This preference for solid floors was particularly marked (88%) when the animals were resting and much less during activity (55.4%). Since the rats were observed to spend 70 to 75% of their time resting, it was concluded that their welfare was likely to be improved by housing them on solid floors.