In the Family Pen System piglets and fatteners grow up in species-specific family groups that correspond to the normal social organization of domestic pigs. The feasibility of a technologically improved version of this alternative housing system, originally designed by Alex Stolba, was tested on a commercial farm for two and a half years. Eighty-one litters were born in three family groups within this period. Average cycle length was 170 ± 24 (SD) days, resulting in 2.15 litters per sow per year. All piglets were suckled for at least seven weeks. In 53.8 per cent of the cycles lactational oestrus occurred before the piglets were seven-weeks-old. The litters of sows which did not show lactational oestrus were artificially weaned and returned to the family group as soon as the sow had been served. At the beginning there were problems with piglet health and crushing, but in the last 21 months of the study there was a stable reproductive performance of 19.5 piglets (28-days-old) reared per sow per year (n = 53 litters). Sows that had been raised themselves in the Family Pen System reared 21.4 piglets per year (n = 25 litters). In conclusion, the technologically improved version of the Family Pen System was found to be practicable on a commercial farm.