Farrowing is among the most welfare-critical periods in a sow life, and understanding the behavioural needs of sows during this period reveals why confinement systems cause such significant welfare harm.
Farrowing behaviour reveals the depth of the welfare problem with farrowing crates. A sow approaching farrowing has one of the strongest behavioural drives in farm animal biology: the need to build a nest and give birth in a sheltered, private location. When this drive cannot be expressed, sows show intense frustrated behaviour on the floor of the crate, attempting to nest-build on the bare concrete. The welfare harm is not abstract — it is the repeated frustration of a powerful biological drive at the most vulnerable and physiologically demanding time of a sow reproductive cycle. Farrowing systems that allow nest-building and free movement fundamentally change the welfare quality of this critical period.