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

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.

Welfare of organic laying hens kept at different indoor stocking densities in a multi-tier aviary system. II: live weight, health measures and perching

Multi-tier aviary systems, where conveyor belts below the tiers remove the manure at regular intervals, are becoming more common in organic egg production. The area on the tiers can be included in the net area available to the hens (also referred to as usable area) when calculating maximum indoor stocking densities in organic systems within the EU. In this article, results on live weight, health measures and perching are reported for organic laying hens housed in a multi-tier system with permanent access to a veranda and kept at stocking densities (D) of 6, 9 and 12 hens/m2 available floor area, with concomitant increases in the number of hens per trough, drinker, perch and nest space. In a fourth treatment, access to the top tier was blocked reducing vertical, trough, and perch access at the lowest stocking density (D6x). In all other aspects than stocking density, the experiment followed the EU regulations on the keeping of organic laying hens. Hen live weight, mortality and foot health were not affected by the stocking densities used in the present study. Other variables (plumage condition, presence of breast redness and blisters, pecked tail feathers, and perch use) were indirectly affected by the increase in stocking density through the simultaneous reduction in access to other resources, mainly perches and troughs. The welfare of the hens was mostly affected by these associated constraints, despite all of them being within the allowed minimum requirements for organic production in the EU. Although the welfare consequences reported here were assessed to be moderate to minor, it is important to take into account concurrent constraints on access to other resources when higher stocking densities are used in organic production.

Welfare of organic laying hens kept at different indoor stocking densities in a multi-tier aviary system. I: egg laying, and use of veranda and outdoor area

Multi-tier aviary systems are becoming more common in organic egg production. The area on the tiers can be included in the net area available to the hens (also referred to as usable area) when calculating maximum indoor stocking densities in organic systems within the EU. In this article, results on egg production, laying behaviour and use of veranda and outdoor area are reported for organic laying hens housed in a multi-tier system with permanent access to a veranda and kept at stocking densities (D) of 6, 9 and 12 hens/m2 available floor area, with concomitant increases in the number of hens per trough, drinker, perch and nest space. In a fourth treatment, access to the top tier was blocked reducing vertical, trough and perch access at the lowest stocking density (treatment D6x). In all other aspects than stocking density, the experiment followed the EU regulations on the keeping of organic laying hens. Laying percentage was significantly lower (P<0.05) in D12 compared with the other stocking densities (90.6% v. 94.3% (± 0.7)), most likely due to the concomitant reduction in nest space and drinker availability per hen. No systematic effects of density were found on other laying variables (egg weight, eggs laid outside nests, aviary side preferences). Number of hens using the veranda increased with stocking density. Hens primarily used the range near the house (within 50 m) and hens kept at the lowest stocking density and the smallest group size appeared to use the outdoor area more extensively, based on an assessment of vegetation cover (P<0.05). For the measures reported here, the welfare consequences of increased stocking density were assessed to be minor; additional results are reported in the associated article (Steenfeldt and Nielsen, 2015).