Effect of group size on aggressive reactions to an introduced conspecific in groups of domestic turkeys (Meleagris gallopavo)

Members of the small groups initiated more fights (0.9/0.1) and delivered more aggressive pecks (20.3/5.0) to the introduced bird than members of the large groups. Also, birds originating from small groups initiated more fights (1.4/0.6) and delivered more aggressive pecks (7.4/3.2) than birds from large groups. Group members showed virtually no aggression towards reintroduced members of their own group. We demonstrate that groups of turkey toms react differently to an introduced conspecific depending on their group size and whether the introduced bird is a group member or not.