Intensive Farming

Pig Farrowing Nest Building Behavior

The nesting drive in sows before farrowing is one of the strongest behavioral motivations in mammals, making crate confinement particularly harmful.

Key Facts

Sows begin nesting behavior 24 hours before farrowing
The nesting drive is hormonally driven and cannot be suppressed
Crated sows unable to nest show repetitive rooting movements as vacuum behavior
Provision of nesting material significantly reduces pre-farrowing stress

Welfare Considerations

The pre-farrowing nesting drive in sows is among the most powerful behavioral motivations documented in any mammal. Crated sows unable to nest perform vacuum nesting behaviors as repeated frustration responses. The distress of nest frustration causes cortisol spikes that may affect piglet delivery and neonatal immunity. Even provision of small amounts of nesting material like straw partially reduces this frustration.

What You Can Do

Support crate-free farrowing systems that allow nest building
Advocate for nesting material requirements as minimum welfare standard
Buy pork from operations with free farrowing or nest material provision
Back research into nesting material provision in crated systems as interim welfare improvement