



Completed Research

U.S. Poultry & Egg

Association

1530 Cooledge Road

Tucker, Georgia 30084-7303

Phone: (770) 493-9401

FAX: (770) 493-9257

Funded by

U.S. Poultry & Egg Association For more information contact USPOULTRY or the Investigator(s).

Project No. BRU007

Evaluating hen behavior and physiological stressors during VSD for the development of humane methodologies for mass depopulation during a disease outbreak

North Carolina State University

Kenneth Anderson, Ph.D.

(919) 515-5527, ken_anderson@ncsu.edu

North Carolina State University

PO Box 7608

Scott Hall Room 237

Raleigh, NC 27695

In 2015, the egg industry was hit with the worst highly pathogenic avian influenza outbreak in U.S. poultry history. Timely depopulation was identified as a critical measure to contain the outbreak. Current depopulation methods, including CO 2 kill carts, CO 2 injection and fire-fighting foam, were quickly overwhelmed and prolonged the suffering of infected birds.

The overall goal of this project was to evaluate welfare parameters of ventilation shut down (VSD) for depopulating laying hens in caged systems through monitoring environmental parameters, behavior and stress physiology. The specific objectives were to 1) determine the time to brain death from VSD using electroencephalograms (EEG), and 2) examine the effectiveness of VSD in a multi-level, commercial cage setting.

This project provided the means to develop and evaluate VSD and other depopulation methods including VSD combined with heat (VSDH) and CO 2 (VSDCO). The first aspect of this project was to develop an environmental profile of an individual hen housed in a cage layer facility. Environmental conditions included building volume (3.4 ft3/hen) and temperature, relative humidity (RH) and CO 2 recordings to understand the dynamics within the environment for each method. This allowed for the determination of the duration to time of death (TOD). The environmental temperature, CO 2 and RH were similar at the start of each test at 89 °F, 0.22 percent and 31.6 percent, respectively. At the end of the tests the environmental temperature was highest for VSDH at 107 °F. VSDCO had the highest level of CO 2 at 31.5 percent. RH increased in VSD and VSDH to 62.5 and 66.0 percent, respectively. The high level of RH appears to have contributed to the diminished ability to reduce core body temperature (CBT). At TOD the CBT was highest for VSD (113.1 °F) and VSDH (115.3 °F) while VSDCO CBT was (105.8 °F). The time to reach TOD was longest in VSD at 91 minutes followed by VSDH at 54 minutes and VSDCO with the shortest TOD at 12 minutes. Comparing EEGs and behavior profiles demonstrated that VSD hens spent 82 percent of the time unconscious while the VSDH and VSDCO hens were unconscious 56 percent and 65 percent of the time, respectively. It was also observed that the stress indicator of heat shock protein 70 (HSP70), for hens exposed to stressors such as heat, humidity or CO 2, declined in the VSD and VSDH environments from time 0 to TOD possibly due to the duration of the unconscious state of the hens.