A non-intrusive method of assessing plumage condition in commercial flocks of laying hens
Publication Type: |
Journal Article |
Year of Publication: |
2006 |
Authors: |
A. Bright, T.A. Jones, M.S. Dawkins |
Publication/Journal: |
Animal Welfare |
Keywords: |
animal welfare, feather pecking, feather score, non-intrusive technique, plumage damage, sample size |
Abstract:
Standard techniques for assessing plumage damage to hens from feather pecking typically require capture and handling. Handling of individual birds for plumage assessment is relatively easy in experimental studies; however, close inspection of individual birds in commercial flocks is less feasible because catching birds is difficult, may compromise bird welfare and affect egg production. The aim of this study was to assess a non-intrusive method for scoring plumage damage in a commercial free-ranging flock of laying hens. Plumage damage was scored within a 2 m distance of the birds, without capture or handling, using a 5-point scale for 5 body regions. The feather scores, recorded at a distance, by two independent scorers were compared (distance scores), and were then compared with feather scores recorded by a scorer who caught and handled the birds to examine the plumage damage closely (capture scores). There was a significant and positive correlation between the distance scores and the capture scores, and the mean correlation coefficient for all plumage score traits was 0.89. There was also a significant and positive correlation between scorers, and the mean correlation coefficient for all plumage score traits was 0.84. The standard deviation of the residual mean difference between scorers and between methods was less than 1 point for individual body regions and less than 1.5 points for the total body score. Large variation in feather damage within a flock and small sample size increased the standard error of the mean total feather score. When feather damage variation within flocks is low (ie little observed feather damage), the current industry standard of scoring a sample of 100 birds is likely to provide a reliable estimate of flock feather damage; however, when there is large variation within birds of a flock (ie considerable observed feather damage) ≥200 birds should be inspected to accurately monitor changes in plumage condition. The non-intrusive method of feather scoring described in this paper may be useful for commercial-scale feather pecking studies or for farmers who need to assess the plumage damage of their flocks reliably, quickly and with minimal disturbance or stress to the birds.