Table 1.
Three different group sizes (GS) were tested (10, 20 and 40) for each original phenotypic appearance (PA) treatment: 100% U (100U), 30% (30M/70U), 50% (50M/50U), 70% (70M/30U), 100% M (100M)). U: Unmarked, M: Marked. Originally heterogeneous groups: 30, 50 and 70% altered from day one were used as controls. Adapted from Marin et al. [47].
Table 2.
Ethogram defining the aggressive interactions recorded: Aggressive pecks, chases, leaps, threats and fights.
Fig 1.
Total aggression (interactions per bird/40 min).
Frequency of total aggression per bird at T0 (27–28 weeks; 1A), T1 (35–36 weeks; 1B), T2 (39–40 weeks; 1C) and T3 (45–46 weeks, 1D). Bars represent means ± SE. M = marked; U = unmarked. Phenotypic appearance (PA) treatments: originally homogeneous (100U, 100M) and controls (30M/70U, 50M/50U, 70M/30U). Different letters denote significant differences among PA treatments at P<0.05.
Fig 2.
Changes in total aggression (interactions per bird/40 minutes) for each phenotypic appearance (PA) treatment across time.
Changes in total aggression per bird for each PA treatment; originally homogeneous groups (100U, 100M) and controls (30M/70U, 50M/50U, 70M/30U), across time periods: T0 (27–28 weeks), T1 (35–36 weeks), T2 (39–40 weeks) and T3 (45–46 weeks). Different letters denote significant differences across time (P<0.05).
Fig 3.
Directionality of aggressive interactions across time.
M = marked; U = unmarked. Differences between observed and expected aggressive interactions (means ± SE) for each possible interacting pair (MM, MU, UM and UU) and phenotypic appearance (PA) treatment: originally homogeneous (100U, 100M), and controls (30M/70U, 50M/50U, 70M/30U). 3A) T0: 27–28 weeks; 3B) T1: 35–36; 3C) T2:39–40; 3D) T3:45–46. Different letters indicate significant differences among interacting pairs within the same PA treatment.
Fig 4.
Directionality of aggressive interactions at T3.
M = marked; U = unmarked. Differences between observed and expected aggressive interactions (means ± SE) at T3 for each possible interacting pair (MM, MU, UM and UU) and phenotypic appearance (PA) treatment: originally homogeneous (100U, 100M) and controls (30M/70U, 50M/50U, 70M/30U), according to group size (GS 10, 20 or 40 birds). Different letters indicate significant differences, within each GS and PA treatment, for each type of interacting pair (P<0.05).