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MAT-SLF-Matprogr.:Prosj.fullfin.av SLF

Rearing laying hens: development of optimal methods that safeguard welfare and productivity (218898)

Awarded: NOK 3.2 mill.

All aims described in the contract are now completed. The main findings are described in the following. Aim 1) De Haas et al. (2014) shows that risk factors for poor feather quality in adult laying hens include damaging pecking at five weeks and elevated fearfulness during rearing. Risk factors for poor feather quality associated with the adult environment include large group size, high fear of humans, and housing on the floor compared to housing in aviaries. Use of special strategies in the production period to improve feather quality have a beneficial effect. Examples of such measures are playback of radio, giving birds stones that stimulate them to peck substrates, use of round water pans and inclusion of males in the flock. Janczak and Riber (2015) summarise risk factors for poor welfare related to rearing laying hens and suggest practical measures for improving laying hen welfare. Aims 2a and 2b: Tahamtani et al. (2016) show that access to a paper substrate the first weeks of life increases feather quality at 30 weeks of age, but does not influence feather pecking. Access to environmental enrichment in adult laying hens, on the other hand, reduces the frequency of gentle feather pecking in adult birds. Brantsæter et al. (2016) show that access to a paper substrate the first weeks of life and access to environmental enrichment in adult laying hens reduces fearfulness at 30 weeks of age. Aim 2c) Tahamtani et al. (2014) show that birds reared in aviaries express behavioural signs of better welfare than birds reared in cages at 19 weeks of age, but not at 21 weeks of age. On the other hand, mortality throughout the production period was 5.52% for birds reared in aviaries, but only 2.48% for birds reared in cages. The main conclusion is therefore that birds that are going to produce in furnished cages should be reared in cages and not in aviaries. Brantsæter et al. (2016) show that rearing in cages produces birds with higher fearfulness than rearing in aviaries. Aim 3: Tahamtani et al. (2015) show that rearing in a stimulus-poor cage environment has long-term negative effects on spatial cognition in laying hens compared with rearing in a more complex aviary environment. Tahamtani et al. (2016) sought to test the effect of early exposure to a complex environment on activity in the dopaminergic system of the brain but showed no effects of rearing in aviaries compared to rearing in cages. Brantsæter et al. (2016) show, similarly to the articles mentioned under aim 2c, that rearing in cages produces birds with higher fearfulness than rearing in aviaries. The same studies also show that rearing birds in aviaries increases their use of three-dimensional space (shelves and perches in the home pen). In addition to the scientific articles mentioned above, we have produced popular scientific articles directed at the industry, lectures at related national meetings, lectures at international scientific conferences, film clips for YouTube and online articles. Also, we have conducted a survey as an attempt to map the relationship between producers perception of production conditions and challenges during the production period. The work is expected to be published shortly (Brantsæter et al. 2017). We also have partners that are publishing an article that deals with epigenetic effects of early environmental enrichment by using samples collected in experiments described under sub-goal 3 (Pertille et al. 2017). Fernanda Machado Tahamtani defended her PhD thesis fall 2016, and Margrethe Brantsæter aims to defend her dissertation in November 2017. Both candidates have moved on to new jobs.

After the ban on conventional cages that will be enforced in 2012 nearly all Norwegian egg laying hens will be reared in aviaries and then housed in aviaries or furnished cages during the laying period. Producers already using these housing systems interm ittently report serious problems with fearfulness, stress, feather pecking and feather loss, and inadequate use of resources. Fear may cause panic reactions and death by suffocation when birds pile up on one another. Stress is associated with inhibition o f growth, a compromised immune system, and decreased productivity. Inadequate use of resources (feed, water, perches, and nest boxes) results in increased mortality and floor eggs. Feather pecking and feather loss reduce feed conversion and may progress t o cannibalism. These problems have a larger impact in aviaries and furnished cages than in conventional cages because of the greater number of animals involved, and the costs to animal welfare and the producers' economy can be substantial. There is no nat ional poultry breeding program in Norway and beak trimming is prohibited. It is therefore essential to develop practical methods of improving welfare and productivity by optimizing rearing methods and management routines. This is the main goal of the prop osed project. The basic research in this project aims at producing new knowledge to help understand how rearing conditions influence cognitive, emotional and physiological development in laying hens. Close collaboration with the poultry industry and large scale studies at conventional farms will ensure the relevance of this research. Knowledge gained through the project will be actively shared with industry representatives and producers and will aim at facilitating a smoother transition from conventional cages to aviaries and furnished cages, thereby contributing to ensuring the welfare of laying hens in future housing systems and the competitiveness of Norwegian egg producers.

Publications from Cristin

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MAT-SLF-Matprogr.:Prosj.fullfin.av SLF