found that restriction of nest-building behaviour due to a lack of space or substrates in prepartum sows increased stress, and led to an increase in farrowing duration when sows were housed in the same environment prepartum and during farrowing. Current findings, however, showed that sows crated from the start of farrowing tended to have longer farrowing duration for the first ten piglets than sows crated from the prepartum period.