This study looks at the short term effects of converting a gestation style barn into a group housing barn and how the change in pen size and sow mixing causes or impacts skin lesions, body condition and reproductive performance. 285 sows were put into groups of 11 to 31 sows and held in either large or small pens. Also 98 sows were held in gestation crates. The bodies of the pigs were assessed before  they entered the specific housing unit and after they left. Also recorded was piglet birth weights, liveborn piglets and stillborn piglets. Body condition was not effected by group housing in any pen size or space allowance. Group housed sows initially had more skin lesions but it did not depend of size of the pen or space allowance, and the occurrence of lesions decreased over time. Group housed sows had slightly heavier piglets and larger litter sizes. Switching to sow housing did not effect body condition or effect reproductive performance, skin lesions were a temporary side effect of mixing.