P-values of the integrated haplotype score (iHS) for (a) the high feather pecking line (HFP, nSNP = 22,425), (b) the low feather pecking line (LFP, nSNP = 23,084) and (c) their combination (nSNP = 16,766). The dashed lines indicate the nominal level of significance p ≤ 10−5.