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This paper describes the introduction of a modified caging system and the benefits to both the animals and staff. The removal of metal grids at the bottom of the cage, and the introduction of direct access to a substrate mixed with cereals and seeds, had a beneficial effect on the psychological well-being of [single-housed] macaques by allowing foraging and, in our experience, up to 60% of our macaques' day is now spent in this pursuit.