Gas Analysis for Humane Poultry Euthanasia

January 12, 2021 at 9:59 pm | Updated January 12, 2021 at 9:59 pm | 5 min read

On-farm euthanasia is sometimes necessary. The method for this type of euthanasia must be efficient and easy, as it is performed by a single operator. The procedure must also be humane and, in many places, it must meet stringent governmental standards. It must also meet the demands of consumers, and be sensitive to the conditions of the animal farms. To find the most humane method of euthanasia, an experiment was conducted to check the efficacy of euthanasia protocols for both small and large animals using precise data collection.

Finding The Most Humane Method of On-farm Euthanasia

The need for on-farm euthanasia of poultry may arise due to disease, poor-performing poultry, or natural disaster.

Euthanasia must be undertaken with proper care so that ending the life of the animal is done in a humane way that minimizes or eliminates pain, fear, anxiety, and distress to the bird.

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Governments across the globe have formulated regulations specifying codes of practice and industry standards for the methods of euthanasia that are allowed.

The technical equipment and practices used must ensure the welfare of the animals, as well as the safety of the farm personnel. The poultry must be rendered unconscious swiftly and not recover sensibility during the process.

The regulations also emphasize compassion as well as the skills of the person euthanizing the poultry. Since the euthanasia of poultry is usually handled by a single person, the method chosen must be easy and efficient enough to be handled by an individual.

Cervical dislocation (CD) is the common method used for on-farm euthanasia; however, it is difficult to perform in the case of large birds like turkeys.

Therefore, scientists Boyal, Buhr, Jacobs, and Bourassa, wanted to test the effectiveness of some other commercial methods, such as Koechner Euthanizing Device (KED), Turkey Euthanasia Device (TED), carbon dioxide (CO2), and electrical euthanasia as mobile alternatives. The CD method was used as a control.

Several methods use CO2, as the gas is inexpensive, nonexplosive, nonflammable, and poses minimal risk to farm personnel when the proper equipment is used. In this experiment, scientists were trying to assemble a mobile apparatus that could meet all of these objectives.

Each euthanasia method was tested on five separate days for each type of bird. It was tested on three categories of birds:

  • 54 Broad Breasted White turkeys (23 males and 31 females)
  • 262 broilers (131 males and 131 females)
  • 120 Beltsville Small White turkeys (76 males and 44 females)

Finding an Accurate Device to Measure Carbon Dioxide

In all other methods, only the tested device was needed. However, for CO2 asphyxiation, the scientists also needed a device to monitor the levels of the gas.

The level of CO2 is crucial during euthanasia. If the levels are too low, the birds are not rendered unconscious, and if levels are too high, the animals suffer distress. To be able to make recommendations on the timing of gas use, the measurements during the experiment had to be accurate.

Moreover, the scientists needed to find a method that could continuously monitor the level of CO2 and not just make trigger measurements. Due to the high number of experiments, and eventual single-operator use, the process also needed to be easy to perform.

Solution: The F-920 Check It! Gas Analyzer.

Scientists conducted gas asphyxiation on poultry using CO2 by assembling a unit with easily available components. To measure CO2 levels, they chose the F-920 Check It! Gas Analyzer.

This device rapidly measures CO2 in a range of 0-100%. It measures the gas using infrared sensors and pyroelectric detectors.

Figure 1. “Multistage CO2 administration, showing CO2 concentration, O2, air RH, and temperature during a single run lasting 4 min,” Gerritzen et al. 1997. (Image credits:

Rather than using a four phase increase (Figure 1), the scientists decided upon a two-phase approach. The CO2 cylinder connected to the apparatus was opened so that the operator heard a hissing sound. In step one, the valve was opened for 20 seconds and CO2 was maintained at 60%. After one minute the valve was opened again for another 30 seconds to reach 70% CO2 levels.  

The scientists were able to fix the length of time to open the valve in both the steps by monitoring the levels of CO2 with the F-920 Check It! Gas Analyzer.

Using the F-920, the scientists were confident in their measurements and could recommend that operators would not need to measure CO2 levels if they follow the timings suggested for opening and closing the valves.

Benefits of Using the F-920 Check It! Gas Analyzer

Only one attempt was allowed during each application of the euthanasia method, and results were judged after four minutes.

Therefore, the speed and accuracy of the F-920, manufactured by Felix Instruments Applied Food Science, was crucial in conducting this time-sensitive and demanding experiment. The tool has a resolution of 0.01%, and individual readings were obtained in 6 seconds. This level of precision was necessary to find the exact protocol that would maintain optimum CO2 levels to desensitize and euthanize the birds properly.

The device could accommodate the large data set, as it has a storage capacity of a 16 GB SD card. Using Bluetooth, the scientists transferred the data directly to their computer for statistical analysis.

The battery in the F-920 lasts for more than eight hours, so it was possible to complete the tests of each category of birds in a single day. The backlit display was easy to read even in dim-lit conditions and functioned perfectly in a broad temperature and humidity range.

All the Alternative Methods were Functional

Scientists used the manufacturer’s brochures to test KED and TED. For the CO2 and electrocution, they used the standard operating procedures (SOPs).

Euthanasia success is defined as no movements after four minutes of the application. The success rates were comparable in all the methods. In all, a few birds survived and the success rate was

  • 97% for CD
  • 98% for KED and TED
  • 97% for carbon dioxide
  • 99% for electrocution

So, all methods can be used when CD is not feasible, as in the case of large birds like turkeys. Moreover, the scientists found that there was no difference between the sexes and the broilers and turkeys in the results.

Mass euthanasia by CO2 is more common than that of individual birds, so the portable apparatus designed by this study can provide increased portability in the use of this method. However, in comparison to the other methods which need only 15 seconds, the CO2 method requires four minutes to complete. The scientists, therefore, recommend this method only if individual-bird euthanasia is infrequent.

Precise Tools

Accurate tools can not only help scientists in improving food production but also make conditions for animals more humane. By providing exact protocols and equipment, scientists can also make work and life easier for farm personnel. This way it is also possible to control the spread of disease and improve animal production on farms.

Vijayalaxmi Kinhal
Science Writer, CID Bio-Science
Ph.D. Ecology and Environmental Science, B.Sc Agriculture

Feature image courtesy of cjuneau.


Boyal, R.S., Buhr, R.J., Harris, C.E., Jacobs, L. & Bourassa, D.V. (2020). Equipment and methods for poultry euthanasia by a single operator. Journal of Applied Poultry Research,
29 (4),

Frickle, J, & Schwean-Lardner. (2014). Euthanasia in poultry: Why, when and how. Retrieved from

Ministry of Agriculture, Food, and Rural Affairs. (2020, Nov 24). Poultry Euthanasia Methods for On-Farm Mass Depopulation. Retrieved from

M.A. Gerritzen, B. Lambooij, H. Reimert, A. Stegeman, B. Spruijt. (1997). On-farm euthanasia of broiler chickens: effects of different gas mixtures on behavior and brain activity. Poult. Sci, 83 (1997), pp. 1294-1301.

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