Acknowledgements Book of abstracts - Publicaties - Vlaanderen.be

Britta Scholz presents Poster 100 during the poster sessions in the Aula.
Session theme 8: Application of welfare assessment protocols
172
Poster 100
DIFFERENT HOUSING SYSTEMS FOR LAYING HENS: A META-
ANALYSIS OF SELECTED WELFARE AND BEHAVIOURAL TRAITS
B. Scholz 1 , S. Rönchen 2 , H. Hamann 2 , O. Distl 2
1 Institute for Animal Welfare and Animal Husbandry, Friedrich-Loeffler-Institute, Celle, Germany
2 Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, Hannover,
Germany
The objective was to assess selected welfare and behavioural traits of four layer strains kept in
different housing systems by applying the tool of meta-analysis.
The study was carried out from 1999 to 2006 at two experimental farms and included data of ten
laying periods (15 studies), comprising 4, 553 hens in total. Data were collected by different authors
using identical methods. Housing systems tested were conventional cages (CC), furnished cages
(FC), small group systems (SGS), an aviary (AV) and an intensive free range system. Least square
means of the traits bone strength, mortality (all systems), keel bone status, foot pad health, plumage
condition, exploratory behaviour (pecking against objects/pecking in dust baths),
standing/walking/dustbathing on wire floor and perch use (standing or sitting, resting) were chosen
for meta-analysis. LSM given by the included studies were weighted with their squared, reciprocal
standard errors and meta-analysis was conducted using a linear weighted least square model.
Housing system significantly effected humerus and tibia bone strength, sole pad hyperkeratosis,
mortality and dustbathing on wire floor (p