Farrowing Nest Building in Pigs: A Welfare Imperative

The biological drive to build a nest before farrowing is a fundamental behavioral need in sows, with significant welfare implications for confinement systems.

Key Facts

Nest building is a highly motivated pre-farrowing behavior in sows, beginning 6-12 hours before birth
In natural conditions, sows travel up to 7 km to find suitable nesting sites
Sows in farrowing crates cannot perform nest building and show high levels of frustration behavior
Providing straw or other nest-building materials significantly reduces sow stress before farrowing
Frustration of nest building is associated with higher cortisol levels and longer parturition duration
Some evidence suggests frustrated nest building impairs maternal behavior postpartum
Loose farrowing systems with nesting material provided represent the welfare-positive alternative to crates

Welfare Considerations

The frustration of pre-farrowing nest building in crated sows causes measurable suffering - sows in crates perform vacuum nest-building behaviors (pawing at floors, rooting the ground) that indicate thwarted behavioral motivation. This is not a minor discomfort but a significant welfare cost experienced by millions of sows multiple times per year. Providing nest material in crates, or transitioning to loose farrowing systems with nesting areas, addresses this need. The welfare science is clear; the implementation requires industry and policy commitment.

What You Can Do

Support pork producers that have transitioned to loose farrowing systems with nesting material
Advocate for legislative requirements providing nesting material to all sows before farrowing
Choose pork certified under higher welfare schemes that address farrowing system standards
Support research into farrowing systems that protect both sow welfare and piglet survival
Share information about sow nesting needs with others interested in farm animal welfare