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

Abstract

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/m 2 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).

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

“…Below is a summary of the experimental design; the full description can be found in Steenfeldt and Nielsen (2015).…”

“…All hens were offered a pelleted and crumbled organic compound layer diet with an average protein content of 205 g/kg dry matter (DM) and a metabolisable energy of 10.6 to 11.3 MJ/kg (see Steenfeldt and Nielsen (2015) for detailed chemical analyses) ad libitum during the experimental period from 18 to 65 weeks of age. The chain feeding system was activated at regular intervals five times per day from 0730 h (first feeding) until 2030 h (last feeding).…”

“…It should be noted that the number of levels the birds can access is usually higher than the number of tiers imply, as each tier may have more than one level. A detailed description of the use of multi-tier aviaries in organic egg production in Europe can be found in Steenfeldt and Nielsen (2015).…”

“…Except for the stocking density in D12, the experiment followed the EU regulations on the keeping of organic laying hens (EC 889/2008(EC 889/ 2008. In a preceding article (Steenfeldt and Nielsen, 2015) we reported the results on egg production, laying behaviour, and use of veranda and outdoor area. In this article we present results on live weight changes, and various health measures, as well as the hens' use of perches.…”

“…In this article we present results on live weight changes, and various health measures, as well as the hens' use of perches. The associated article (Steenfeldt and Nielsen, 2015) should be consulted for a full evaluation of the consequences for production, behaviour and welfare of allowing more hens per available floor area in these types of organic egg production systems.…”