To provide the opportunity for ‘proper manipulation’, enrichment materials should:

Be edible, preferably including some nutritional/digestive benefit

Be chewable, providing pigs with information such as taste

Be rootable, allowing pigs to investigate, using their snout

Be destructible, allowing pigs to thoroughly assess any material (Studnitz et al., 2007).

Foraging in silage

“pigs must have permanent access to a sufficient quantity of material to enable proper investigation and manipulation activities, such as straw, hay, wood, sawdust, mushroom compost, peat or a mixture of such, which does not compromise the health of the animals.” (EU Directive 2008/120/EC, Annex 1, para 4)