Figure 2. The distribution of differences in aggression score of male fowl in duels.

The winning, dominant male either had a higher aggression score compared to the losing, subordinate male (Dom>Sub, black column), the same aggression score (Dom = Sub, grey column) or a lower score (Dom<Sub, white column). When aggression scores differed between the two males of a pair, showing higher levels of aggression during the initial part of the duel was associated with winning it (12 cases vs 1 case).