Enriched cages (i.e. those that contain more space per hen, a nest box, a littered area, and perches) for laying hens are likely to become increasingly common with the proposed ban of the battery cage (Council Directive 99/74/EC), which is due to take effect in 2012. Relevant studies on the full impact of this housing system on the health and welfare of the laying hen have been limited, and confounded by factors such as experimental group size (usually small) compared to commercially available cage sizes (housing as many as 60 birds). Research to date on enriched cages has had varying results, particularly on the levels of mortality related to cannibalism. In light of the ban on beak trimming (which takes effect in 2011), relevant information on the most effective way to house birds in these systems without jeopardising their welfare is critical. Furthermore, it is as yet uncertain which strains of laying hens are better suited to the enriched cage environment than others.
The main objectives of this project are to examine the health and welfare of both a brown and white laying strain of hen in different types of commercially-available enriched cages. This study will examine two commercially-available cage designs (by Valli and Big Dutchman) with three different group sizes per cage design (ranging from 20 – 80), and examine not only behaviour of birds within cages, but parameters of health and welfare (such as keel bone condition, tibia breaking strength, immune function, and evidence of feather pecking and cannibalism). In addition, we will examine the 10 colony cage size manufactured by Big Dutchman (no comparable cage is available from Valli). The outcomes of this project will be to advise government and industry on the pros and cons of a variety of factors (genotype, group size, cage design) related to enriched cage systems before their use becomes more prevalent in 2012.