Indoor or outdoor sows were mated to boars, and their progeny were raised in outdoor paddocks, straw yards, or fully-slatted pens. The trial ran from the period when the pigs were an average of 30 kg to 80 kg liveweight. Welfare was assessed using a combination of different health criteria. Criteria examined were bursitis of the hock, injuries to the body, prevalence of stomach ulcers, and prevalence of enzootic pneumonia. Piglets from outdoor sows had less body injuries and lung damage due to pneumonia than piglets from the indoor sows. When housed in outdoor paddocks or straw yards, piglets had significantly less bursitis of the hock, body injuries, stomach ulcers, lung damage, deaths, and morbidity (having to be removed from the trial due to health problems) compared to piglets raised in fully-slatted pens. There were no significant interactions between housing and type of sow the piglets were born of for any health parameters measured. The overall effect of season on pig welfare could not be adequately determined due to conflicting health criteria. In conclusion, pig welfare was improved when the pigs were raised in either outdoor paddocks or straw yards compared to fully-slatted pens.