Farrowing crates confine sows around the time of birth to prevent them from crushing piglets, but impose severe behavioral restrictions on the sow during a period of high behavioral motivation for nest building and activity.
The farrowing crate imposes behavioral restriction at a time of maximum behavioral motivation. The sow's drive to build a nest before birth is one of the strongest motivations in her behavioral repertoire, and confining her in a crate that prevents any meaningful nest-building behavior causes measurable frustration and stress. While the prevention of piglet crushing is a genuine welfare concern, the evidence from Scandinavian loose farrowing systems demonstrates that this goal can be largely achieved through well-designed alternatives. The welfare cost of crate confinement needs to be weighed against the welfare of individual piglets at risk of crushing in poorly designed loose systems.