Farmed Pig Farrowing Nest Building Motivation

The motivation of sows to build nests before farrowing is one of the strongest and most well-documented behavioural drives in domestic pigs. Preventing nest building in conventional farrowing crates causes significant frustration and stress.

Key Facts

Wild and feral pigs spend several hours building elaborate nests before farrowing, collecting grass and other materials
Nest building motivation increases dramatically in the 24 hours before birth and is driven by hormonal changes
Sows in farrowing crates show redirected nesting behaviour including rooting at the floor and bar-biting when nesting material is unavailable
Providing even simple nesting material such as straw or paper reduces pre-farrowing stress significantly
Nesting behaviour serves thermoregulatory functions for newborn piglets who cannot regulate their own temperature
Studies using preference tests show sows choose to nest before farrowing even when food is available
The strength of the nesting motivation is comparable to hunger and thirst in terms of behavioural priority
Free-farrowing and loose-housed systems that provide nesting material achieve substantially better sow welfare around parturition

Welfare Considerations

The frustration of nest building motivation in conventional farrowing crates represents a profound welfare compromise. Sows are prevented from performing one of their most strongly motivated pre-parturition behaviours. The redirected behaviours they exhibit - rooting fruitlessly at concrete, biting bars - are indicators of the frustration this causes. Providing nesting material in farrowing systems, whether crated or free-farrowing, is one of the most welfare-positive changes available to farrowing management. The cost of providing straw or paper is minimal compared to the welfare benefit.

What You Can Do

Support pig welfare standards requiring nesting material provision for farrowing sows
Choose pork from farms certified for free-farrowing or enriched farrowing with nesting material
Advocate for farrowing crate phase-out legislation that includes mandatory nesting material in alternatives
Learn about sow nesting motivation to understand why farrowing crate design is a welfare priority