Risk Factors Associated with Contact Dermatitis, Lameness, Emotional state and Fear of Humans in Broiler Flocks09 December 2013
An EU study reveals that three management factors - the length of the dark period at three weeks of age, litter quality and slaughter age - contribute to the welfare of broilers, as judged by the birds' behaviour and scores for footpad dermatitis, hock burns and lameness.
A multinational European group has investigated the potential risk factors associated with contact dermatitis, lameness, negative emotional state and fear of humans in broiler chicken flocks, publishing their report in Poultry Science.
The objectives of this study, explain first-named author, A.W. Bassler of the Swedish University of Agricultural Sciences in Uppsala and co-authors, were:
- to identify determinants of poor welfare in commercial broiler chicken flocks by studying the associations between selected resource-based measures (RBM, potential risk factors), such as litter quality and dark period, and animal-based welfare indicators, such as foot pad dermatitis and lameness, and
- to establish the breadth of effect of a risk factor by determining the range of animal welfare indicators associated with each of the risk factors (i.e., the number of animal-based welfare indicators related to a specific RBM).
A total of 89 broiler flocks were inspected in four European countries (France, Italy, the United Kingdom, and the Netherlands) in a cross-sectional study.
The animal-based welfare indicators were contact dermatitis (measured using scores of foot-pad dermatitis and hock burn, respectively), lameness (measured as gait score), fear of humans (measured by the avoidance distance test and the touch test) and negative emotional state (measured using qualitative behaviour assessment, QBA).
In a first step, risk factors were identified by building a multiple linear regression model for each animal-based welfare indicator.
Litter quality was identified as a risk factor for contact dermatitis. Length of dark period at three weeks of age (DARK3) was a risk factor for the touch test result. DARK3 and flock age were risk factors for lameness, and the number of different stockmen and DARK3 were risk factors for QBA results.
Next, the animal-based welfare indicators were grouped according to risk factor and counted.
Then, in a second step, associations between the animal-based welfare indicators were investigated using common factor analysis.
The breadth of a risk factor’s effect was judged by combining the number (count) of animal-based welfare indicators related to this factor and the strength of association between these indicators.
Flock age and DARK3 appeared to affect several weakly correlated animal-based welfare indicators, thus indicating a broad range of effects.
Bassler and co-authors concluded their findings suggest that manipulation of the predominant risk factors identified in this study - DARK3, litter quality and slaughter age - could generate improvements in the related animal-based welfare indicators and thereby enhance the birds’ overall welfare status.
Bassler A.W., C. Arnould, A. Butterworth, L. Colin, I.C. De Jong, V. Ferrante, P. Ferrari, S. Haslam, F. Wemelsfelder and H.J. Blokhuis. 2013. Potential risk factors associated with contact dermatitis, lameness, negative emotional state, and fear of humans in broiler chicken flocks. Poult. Sci. 92(11):2811-2826. doi: 10.3382/ps.2013-03208
You can view the full report (fee payable) by clicking here.