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Animals 2019, 9(2), 47;

Euthanasia: Manual versus Mechanical Cervical Dislocation for Broilers

Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA 24061, USA
Department of Poultry Science, Auburn University, Auburn, AL 36849, USA
Department of Poultry Science, The University of Georgia, Athens, GA 30602, USA
USDA-ARS, US National Poultry Research Center, Athens, GA 30605, USA
Author to whom correspondence should be addressed.
Received: 19 January 2019 / Accepted: 28 January 2019 / Published: 1 February 2019
(This article belongs to the Section Animal Welfare)
Full-Text   |   PDF [325 KB, uploaded 2 February 2019]   |  

Simple Summary

Poultry are euthanized for several reasons, most commonly because a bird is sick or injured and unable to eat or drink. Euthanasia can be a challenge to perform, especially when birds are heavy, like broiler chickens (produced for meat). Manual cervical dislocation (CD), or “breaking the neck”, is the most commonly applied method, but can be challenging. Therefore, using a tool (the mechanical method) such as the Koechner Euthanizing Device (KED) could be an alternative. Here, we aimed to compare CD with KED application for their impact on duration of induced reflexes and time to brain death. We assessed loss of brain stem reflexes, which indicate deep unconsciousness and/or brain stem death, and cessation of musculoskeletal movements. We applied both methods (CD and KED) to 200 broilers of 36, 42, or 43 days old on 3 experimental days. On days 2 and 3 an additional method was added, in which the bird’s head was extended at a ~90° angle after the application of the KED (KED+). Our study indicated brain stem death occurred sooner when birds were euthanized with CD compared to KED or KED+; all reflex durations were sustained for longer in the KED and KED+ birds.


The aim was to assess the onset of brain stem death for two euthanasia methods—manual cervical dislocation (CD) versus the Koechner Euthanizing Device (KED). Over three days broilers of 36 (n = 60), 42 (n = 80), or 43 days old (n = 60) were euthanized. On days 2 and 3, a treatment was added in which the bird’s head was extended at a ~90° angle after application of the KED (KED+). On those days, gap size was recorded between the skull and atlas vertebra by 1-cm increments. The onset of brain death was assessed by recording the nictitating membrane reflex, gasping reflex and musculoskeletal movements (sec). Additionally, skin damage and blood loss were recorded (y/n). On all days, CD resulted in quicker loss of reflexes and movements compared to KED or KED+. Reflexes returned in 0–15% of CD birds, 50–55% of KED birds, and 40–60% of KED+ birds, possibly regaining consciousness. Skin damage occurred in 0% of CD birds, 68–95% of KED birds, and 85–95% of KED+ birds. On day 2 (p = 0.065) and 3 (p = 0.008), KED birds had or tended to have a narrower skull-to-atlas gap compared to CD and KED+ birds. Based on our results, CD would be the recommended method for broilers. View Full-Text
Keywords: culling; killing; poultry; euthanasia; cervical dislocation; reflexes; animal welfare; brain stem death culling; killing; poultry; euthanasia; cervical dislocation; reflexes; animal welfare; brain stem death

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Jacobs, L.; Bourassa, D.V.; Harris, C.E.; Buhr, R.J. Euthanasia: Manual versus Mechanical Cervical Dislocation for Broilers. Animals 2019, 9, 47.

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