Housing of farrowing and lactating sows in farrowing crates can cause a number of welfare problems. Recently, alternative farrowing pens have been developed which allow the sow to turn around and move freely. In this experiment a conventional farrowing crate (C; 5.0 m(2); the sow is crated permanently), the Trapez pen (T; 6.7 m(2); with a crate opened two days after farrowing) and a modified FAT2 pen (F; 6.7 m(2); loose-housing system with nest and dunging area), were compared. The behaviour of sows was recorded from 6 hours ante partum to 24 hours post partum and analysed for duration of birth, number of posture changes, activities indicating nest building and piglet crushing. Sows were inspected for skin lesions at days 5 and 23, post farrowing. There was a tendency for longer birth duration and restlessness during farrowing when sows were crated. Sows in F and T crushed more piglets than sows in C but only few sows were concerned. In C more sows had severe injuries on the udder and on the limbs than in F and T. It can be concluded that the health and behaviour of farrowing and lactating sows are negatively affected when being housed in conventional pens with crates and slatted flooring. Further development is required to minimise piglet crushing in loose-housing systems.