Effect of slaughtering age in different commercial chicken genotypes reared according to the organic system: 1. Welfare, carcass and meat traits

The carcass and meat quality of three different commercial chicken genotypes reared according to the organic system and slaughtered at two different ages (70 and 81 days) were compared. The used genotypes were Naked Neck (CN1), Kabir (KR4) and Ross 308 (R). All animals were raised in the facilities of a big Italian company, in production units of 3000 birds. Before slaughtering, plumage conditions, foot pad dermatitis as well as qualitative traits of carcasses, such as skin damage and the presence of breast blisters, were registered (n=50). Naked Neck birds showed the best plumage conditions at both ages; the other genotypes had similar body conditions showing a dramatically worsening at the end of rearing cycle (81 days), mainly at breast level. The carcass conformation showed differences mainly for the CN1 genotype, which was more slender with higher proportions of head, neck and legs; thus, ready-to-cook-carcass yield was lower. The meat of CN1 chickens showed lower levels of lipids, pH and brightness values, but higher index of redness. Ross 308 genotype showed a bad welfare status even at 70 days, confirming that the rearing of this strain should not be permitted in organic systems. In conclusion, this study indicates that genotype deeply affects performance, welfare and qualitative characteristics of meat. Regarding the slaughtering age, although the inconsistency of European Commission rules which authorise the reduction of slaughtering age in less mature strains, at 70 days chickens show higher feed efficiency and thinness of carcass and meat.