Effects of indoor stocking density on performance, egg quality, and welfare status of a native chicken during 22 to 38 weeks

Abstract

This study investigated the effects of indoor stocking density on performance, egg quality, and welfare status of a native chicken, Beijing You Chicken (BYC), during 22 to 38 wk. A total of 1,040 19-wk-old BYC pullets were randomly allocated to 4 groups (2 replicates each) and reared in 8 individual floor pens with separate covered shed and uncovered outdoor areas. The indoor stocking densities were 5, 6, 7, and 8 hens/m2, and the birds were fed corn-soybean based diets. The performance was calculated for 22 to 30, 30 to 38, and 22 to 38 wk, and egg quality indices were measured at the end of weeks 26, 29, and 36. The feather cover and gait score of the birds were assessed at the end of weeks 29 and 36. The results showed that average feed intake (AFI) and mortality rate of BYC in the 8 hens/m2 group were higher than other groups during 22 to 30 wk (P = 0.001 and P = 0.005); the egg mass and egg-laying rate were higher in groups with lower stocking density, in contrast to the feed egg ratio during 30 to 38 wk. The AFI, mortality rate, and 38-wk body weight were affected by stocking density during 22 to 38 wk (P < 0.05). Most of egg quality indices were not changed by stocking density (P > 0.05), except for individual indicators, such as Haugh unit at week 26 (P = 0.012) and egg grade at week 29 (P = 0.026). The feather cover and gait scores of birds were affected by indoor stocking density at 36 wk of age, with the 8 hens/m2 group having lower scores than the 5, 6, and 7 hens/m2 groups (P = 0.042 and P = 0.039), whereas the 7 hens/m2 groups having no difference with the 5 and 6 hens/m2 groups (P > 0.05). Overall, the results suggested that the performance and egg quality of BYC were not significantly affected by equal to or less than 7 hens/m2 under this system (P > 0.05), but 8 hens/m2 had an adverse effect on the performance and welfare status of the native chicken during 22 to 38 wk.