Table 1.

Environmental enrichment materials and objects according to the categories included in the Commission Recommendation (EU) 2016/336, and their main effects on sucker and weaned piglets’ behavior.

Animal	Enrichment	Duration of Behaviour Observation	Main Effect	References
sucker/weaned piglets	black foam rubber matting ***	8 h daily on 3, 10, 19, 26, 33 d of pig’s life	reduction in belly nosing	Bench and Gonyou [84]
sucker/weaned piglets	farrowing pen—straw bedding *	6 h daily on 6, 12, 20, 21, 22, 27 d of pig’s life	increased level of exploration, animal comfort improved	Brajon et al. [82]
sucker/weaned piglets	farrowing pen—wood shavings **, sisal rope **, plastic ball attached to chain ***, newspaper **	4 h daily one day per 2, 3, 9 wks. of pig’s life	at pre-weaning stage—decrease in pen mate manipulation	Telkänranta et al. [81]
	weaners pen—wood shavings **, sisal rope **, plastic chewing toy ***		at post-weaning stage—decrease in severe tail damage
sucker/weaned piglets	farrowing pen—wood bark in a plastic box **	6 h daily on 4, 5, 11, 12, 19, 23 d of pig’s life	baseline of cortisol level on d 1 post-weaning	Yang et al. [79]
weaned piglets	aromatized plastic container **	24 h per 9 d after weaning	decrease of duration of agonistic behavior	Nowicki et al. [88]

* optimal, ** suboptimal, *** marginal materials according to the categories included in the Commission Recommendation (EU) 2016/336 on the application of the Council Directive 2008/120/EC, laying down the minimum standards for the protection of pigs with regards to measures to reduce the need for tail-docking [9].