An increasing number of laying hens are being housed in more complex loose-housed systems but there is a lack of research focusing on the rearing period to prepare them for the laying shed. The first aim of this thesis was to investigate the provision of access ramps during the rearing period to encourage movement between elevated levels. Reduced behaviours indicative of hesitancy was found in young pullets that were reared with previous ramp access. The second aim of the thesis was to look at the effects of rearing in complex three-dimensional environments on the spatial cognitive ability of chicks. If reared with access to complex structures chicks showed improved spatial navigational ability in the detour test and a suggested improved ability to utilise intra and extra maze cues in the rotated floor test. The third aim was to apply these results to a commercial laying farm to look at the application of access ramps to elevated structures during the rearing period and if this had effects on movement between levels in the laying shed. Results demonstrate rearing with access ramps improves structure use at rear and reduces behaviours indicative of hesitant transitions down ramps in the laying shed. Chicks reared with access ramps were found to have better plumage scores at 40 weeks of age compared to the non-ramp reared chicks, suggesting there may be benefits to welfare. The final study aimed to summarise the rearing practices currently used in the UK, highlighting common practices that may require further investigations. In summary, this thesis demonstrates that rearing layer chicks in more complex environments and providing access via ramps to elevated areas may have beneficial impacts on spatial development, movement and welfare in commercial laying systems.
|Date of Award||21 Jan 2021|
- The University of Bristol
|Supervisor||John F Tarlton (Supervisor) & Toby G Knowles (Supervisor)|