This study was conducted to determine if pigs with few littermates present in their new group performed poorly in comparison with litters with several littermates present. It is typically most cost effective to design a grower/finisher barn with permanent pens of the same size. However, with varying litter sizes, there is need for re-grouping once the pigs reach the grower/finisher stage. Once pigs are regrouped they are forced to form a new group identity and this transition may put some pigs at a disadvantage.
In this study litters of similar size were used. Each group was made up of 6 pigs from one litter (majority pigs) and two from another litter (minority pigs). Following regrouping pens were videotaped for 6 hours. These recordings were analyzed for aggression to determine if minority pigs were both dominant, both subordinate, or one being dominant and the other subordinate. It was found that weight gains of both majority and minority pigs did not differ during the study. Littermates did not cooperate to ensure that majority pigs were all dominant. Interestingly, minority pigs continued to associate with one another regardless of their position in the hierarchy. This information suggests that the new group identity does not obliterate the old identity. The study concluded that pigs in the minority are not at a disadvantage in terms of social status or growth.