Laying hens in furnished cages

Wall, Helena (2003) Laying hens in furnished cages. Doctoral diss. Dept. of Animal Nutrition and Management, SLU. Acta Universitatis agriculturae Sueciae. Agraria vol. 406.

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Abstract

Concern for the welfare of laying hens housed in conventional cages has led to a change of the Animal Welfare Legislation in Sweden, implying that cages must provide possibilities for hens to lay eggs in a nest, to rest on a perch and to use litter. Such requirements are also being considered within the whole European Union. The purpose of this thesis is to contribute to the general knowledge of, and further development of, furnished cages, both as regards birds’ use of facilities and their welfare, as well as with regard to production. The furnished cages housed 6 to 16 birds and the genotypes included were the commercial hybrids Lohmann Selected Leghorn (LSL), Hy-Line White and Hy-Line Brown. Passive Integrated Transponders were used in order to record individual bird’s use of litter baths, nests and passages through pop holes in larger cages divided into two halves.

With some exceptions, nest and perches were generally used by 80-90% of the birds, and nest use was affected by nest design. There was a very large variation in the number of days individual birds visited the litter bath, and almost 30% of the birds never entered the baths. Frequent use of litter affected neither a hen’s exterior appearance (feather cover, pecking wounds) nor her estimated level of stress. Providing cages for larger groups of hens with a partition with pop holes, in order to improve their escape possibilities, did not affect any of the measured welfare traits. However, the pop holes were frequently used and the cage proved to work in all practical aspects. Two different measures to reduce egg shell cracks, both reducing the speed of the eggs on their way out of the nest, proved to be very efficient. Egg production and mortality rates were normal and similar to levels recorded in conventional cages. Differences in behaviour, indicators of stress and fear, exterior egg quality and exterior appearance were identified between genotypes. In conclusion, most birds found nests and perches attractive, whereas litter was used to varying extents. With inexpensive measures to reduce egg cracks, the proportion of cracks can be reduced to the level found in conventional cages.