The frequency for genotype −/− (0.60) at the PRLpro2 locus was greater than that (0.06) for +/+ (Table 4), and the effects of PRLpro2 genotypes on broody traits of Blue- shell hens differed (P < 0.05). None of the +/+ hens exhibit broodiness, whereas 42.0% of the +/− and 32.9% of the −/− hens went broody. The chi-squared test (χ2 = 18.12) showed that the incidence of typical broody of +/− and −/− was higher (P < 0.01) than that of +/+. Genotypes +/− and −/− did not differ for any of the broody traits.
As shown in Table 5, the frequency for genotype A (0.88) at PRLR3 locus was greater than that (0.12) for G, whereas TG and CA at PRLR6 exhibited approximately the same frequency. There were no differences (P > 0.05) between genotypes for PRLR3 or PRLR6 for any of the broody traits.