Effects of two different rearing systems (organic and barn) on production performance, animal welfare traits and egg quality characteristics in laying hens

摘要

Alternative housing systems for hen eggs production represents clear evidence of the trend in animal housing and husbandry towards extensive rearing methods. Consumer demand is oriented towards healthy foods controlled not only under a safety point ofview, but also under a welfare assessment of the animals' living conditions. Among the different alternative systems deep litter and organic production in recent years have been improved in Italy. The aim of this study was to evaluate whether differenthousing systems (barn B and organic 0) for laying hens may influence productive performance, fear responses and egg quality characteristics. A total of 4,745 birds were housed in the B system and 2,016 in the O system, both of which were commercial facilities. In each system the same strain (Hy-Line Brown) was housed and layer performance, external and internal egg characteristics, mortality and feed consumption were recorded weekly. Animal reactivity was recorded monthly with the approaching test. Moreover, the Tonic Immobility test was conducted at 70 weeks of age; feather and foot pad conditions were also investigated at the same time. The peak of laying was reached in both housing systems at 25 weeks of age and was higher in organic hens (94.5%) than in barn hens (93.0%). Feed conversion rate during the overall laying period was 2.36 vs 2.20, respectively, in O and B housing systems. There was a significant difference concerning the eggs classified as very dirty, dirty and cracked between the twosystems. The dirty eggs were higher in O system probably due to laying eggs in a free range area, while the higher number of cracked eggs in B system may be due to a significantly less shell thickness in this system. Egg weight increased with layer age in both housing systems. Animals reared in 0 system showed less fearfulness than in B emphasised by the approaching and Tonic Immobility test results. Feather scoring did not evidence any severe plumage damage; statistical analysis showed some significantdifferences in comb and back areas between O and B systems. The hens reared on litter showed more aggressive pecking than the organic hens probably due to difference both in light intensity and in density.