Pigs with access to maize silage manipulated this rooting material more and pen components and pen mates less than pigs with access to chopped straw suggesting that maize silage may provide a better outlet for pigs’ explorative behaviour than straw. Pigs with a high space allowance (obtained by reducing the group size) manipulated the rooting material more. Finally, increased manipulation of pen mates and pen components (abnormal behaviour) during the hour before daily allocation of new rooting material suggests that the amount allocated was insufficient to maintain explorative behaviour directed towards rooting material, and to minimize redirection towards pen components and pen mates, throughout the 24 h.