A factorial experiment was carried out to see how welfare was effected, both long and short-term, by pens size and pen design. The experiment used mated gilt pigs in groups of four. The pigs were unfamiliar with each other and were put through six treatments which were combinations of either large or small pens (1.97 m² per pig or 0.98m² per pig) and pens with or without feeding stalls  and with stall feeding or floor feeding. Pigs were video taped and analyzed on aggressive behavior such as biting and butting. They were watched in the first 90 minutes they were grouped and after that during feeding periods on certain days. Also pigs were inspected for lesions before treatment and during treatment. Pigs were assessed for cortisone levels to determine the long term effects of stress. In the initial 90 minutes, pen size had no effect on the amount of aggressive behavior, also pen design had little effect on aggression. Around feeding the large pen had less incidence of aggression. Pen design also had impacts on aggression, in the treatment with stalls and when the stalls were used, it was found that there was reduced aggressive behavior. While pens without stalls and the use of floor feeding had the most aggressive behavior. Cortisone levels were seen to improve in bigger pens and pens designed with stalls and when stalls were used. Pen size or pen design had no effect on lesions. The article concludes to say there are potential welfare improvements that can come from pen size and pen design but further research is needed to find what pen design and management practices are ideal. Also more research is required to find what behavioral and physiological parameters should be used to measure welfare.

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