Influence of rearing environment on development of perching and dustbathing behaviour in laying hens

Studies have shown that perching and dustbathing behaviour in birds can be affected by how and when the behaviour develops. With the increasing trend away from cages and towards keeping laying hens in larger, more complex housing systems, it is important to improve our knowledge about what chicks need to learn if they are going to be able to fully use perches and litter when these are provided to them as adults. In the first part of this thesis the early use of perches and how this was influenced by the bird´s behaviour during the first weeks of life was investigated at the individual level. Furthermore the relationship between a bird’s spatial ability as a chick and as an adult was investigated by testing birds in two different two-dimensional spatial tests and by observing their use of perches. The aim was to investigate the degree to which birds are hatched with spatial skills or acquire these by using perches. The second part of the thesis dealt with the importance of access to an appropriate, that is to say, functional substrate for the development of dustbathing behaviour. Here comparisons of dustbathing behaviour by birds with different experiences of peat, a preferred dustbathing substrate, were carried out. In addition it was investigated whether birds that had only ever known sham dustbathing would be as motivated to get access to peat for dustbathing as birds reared and used to performing functional dustbathing. It was found that behaviour, such as spending more time underneath the perches, related positively with early perch use and the ability to solve a two dimensional spatial test was related to use of perches in a novel situation as adult. However, the results did not shed any light on whether chicks hatched with good spatial ability or if the spatial ability mostly developed through the use of perches. Dustbathing behaviour was influenced mainly by the substrate and the birds which gained or lost access to peat changed their dustbathing behaviour according to if they dustbathed in peat or on paper. Birds dustbathing on paper performed a less coherent dustbathing behaviour with more long and short bouts than birds dustbathing on peat. Irrespective of treatment all birds were motivated to get access to peat for dustbathing. These results imply that sham dustbathing can not replace functional dustbathing for a hen. In combination, the results of this thesis confirm the importance of giving early access to litter and perches also to the young chick