|Cheng, Heng Wei|
Submitted to: Scientists Center for Animal Welfare Newsletter (Quarterly)
Publication Type: Popular Publication
Publication Acceptance Date: 4/18/2007
Publication Date: 4/26/2007
Citation: Dennis, R.L., Fahey, A.G., Cheng, H. 2007. Marked for Success?: Identification Systems Impact Poultry Welfare. Scientists Center for Animal Welfare Newsletter (Quarterly). p. 21. Interpretive Summary: Artificial marking and tagging for individual identification are an integral part of animal research, including research utilizing animals as models for biomedical, agricultural and wildlife experimentation. A variety of identification systems are available and researchers often choose identification systems based on experimental design and/or convenience, with little knowledge of their effects on the animals or the experimental results. Our research group recently investigated the potential side effects of four popular identification systems used in poultry research, i.e., leg bands, wing bands, neck tags and livestock marker applied to tail feathers. The birds' behavioral and physiological changes associated with these identification systems were examined in comparison with birds bearing no identification marks. Results showed that wing and leg banding systems have a great impact on the social interactions of birds with their cage-mates as compared to neck tags and livestock marker. The findings provide evidence of the side effects of wing and leg band systems on birds' well-being. The data can be adopted by scientists in designing and conducting research, with an emphasis on receiving reliable conclusions and improving animal well-being.
Technical Abstract: Individual identification is a common method used in animal research. This study was designed to examine if various common identification systems, i.e., leg bands (LB), wing bands (WB), neck tags (ST), and livestock marker (LM), have different effects on hens' behavioral and physiological homeostasis. At 18 wk of age, hens were paired in all combinations of treatments and control (C, unmarked hens; n=10) in a novel cage for 5 trials of 1 hr each to test the effects of markers on social behaviors. Increased feather pecking (FP) was exhibited in WB hens compared with C hens (P<0.10) but not in LB, ST or LM hens (P>0.10). Increased FP in hens with WB may suggest an increase in social stress and may lead to increased feather and body damage. No effect of identification treatment was evident on frequency of aggressive behaviors (P>0.10). At 20 wk of age, absolute fluctuating asymmetry (FA), but not relative FA, of shank length and width was more significant in LB hens (P<0.05), and tended to be significant in WB (P<0.10), but not in ST or LM hens, compared to C hens. Asymmetry of the shank is often a result of high stress levels, including social stress. Body weight (BW) measures at 20 wk showed hens with LB, but not WB, ST or LM, were significantly lighter than C hens (P<0.05), possibly as a result of decreased access to resources, increased metabolism or decreased appetite due to elevated stress. Increased FA and decreased BW are evidence of a disruption of the hens’ physiological homeostasis due to increased stress. Leg banded hens also tended to have a lower percentage of heterophils (P<0.10), indicative of increased stress and reduced immunocompetence. Our findings provide clear evidence of the effects of WB and LB systems on hens’ both physiological and behavioral homeostasis, ignoring these effects will possibly lead to misinterpretation of experimental results.