Group housing of sows had a positive effect on parturition, but led to a decrease in litter size by 1.2 alive born piglets per litter and a reduce in mean birth weight of piglets by 70 g; it had no effect on the vitality of piglets. A high birth weight, a long lasting placento-fetal blood transfer and an air temperature of more than 20 degrees C are factors with significant influence on vitality of neonates.