Determining cessation of brain activity during depopulation or euthanasia of broilers using accelerometers

The threat of avian influenza virus is a major concern for poultry growers worldwide. In response to avian influenza virus outbreaks in the United States and the existence of zoonotic strains causing human infection and death in Eastern Asia, a mass emergency depopulation method using water-based foam was developed for floor-reared broilers and turkeys. During foam depopulation, birds cannot be observed directly. As a result, several methods for monitoring bird activity during field depopulation research were explored. Accelerometers were found to be a simple, effective means of detecting motion and subsequently the cessation of motion after terminal convulsions ceased. In a previous study, it was shown that motion cessation may coincide with a lack of measureable brain activity. In this study, broilers were monitored with electroencephalograph, electrocardiograph, and motion sensors and treated with 1 of 3 methods of depopulation or euthanasia (Ar-CO2 gas, CO2 gas, or water-based foam). The differences between the accelerometer motion cessation and electrocardiogram signal stabilization were significant, as were the differences between motion cessation and electroencephalogram silence. Although the differences are statistically significant, these do not invalidate the use of an accelerometer to detect cessation of measurable brain activity during depopulation or euthanasia research.