Larger organic farrowing pens with more opportunities to perform nest building and maternal behaviour are a potential way for better care for the piglets. Behaviour and performance of 60 sows and litters was studied on a commercial organic pig farm during 1.5 years in farrowing pens of 8 or 24m². Video footage was recorded from 24 h before birth of the first piglet until 72 h after birth of the last piglet. Activity and postural changes of the sows, piglets and position of the nest were scored by scan sampling. The results showed more nest building behaviour and lower piglet mortality in larger pens, but without a difference in prepartum activity or risky postural changes postpartum. This outcome suggests that it might be beneficial to provide organic sows more space around farrowing.