Nest building before farrowing is a fundamental behavioral drive in sows that is highly frustrated in conventional farrowing crate systems, causing significant welfare compromise at a critical life stage.
The frustration of nest building is one of the most acute welfare failings of conventional farrowing crate systems. Sows in the hours before farrowing show intense behavioral motivation to build a nest, pacing and rooting repeatedly on concrete floors when materials are unavailable. This frustrated motivation causes measurable physiological stress at a highly vulnerable time. Simple provision of nesting materials substantially reduces this welfare cost at minimal financial expense. The evidence base for nest building provision is sufficiently strong that its absence in commercial systems represents an unjustifiable welfare failure.