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Online GuideKilling poultry

Chicks (less than 72 hours old) and embryonated eggs

Maceration/Instantaneous Mechanical Destruction (IMD)

For the killing of embryonated eggs and day-old poultry, a mechanical apparatus can be used to macerate the animals. There are two types of device currently in use in the UK. The first is a “crushing” design which causes the chicks to be crushed between two rollers which are rapidly rotating. The second approach is a “knife-type” design containing fast moving blades which mince the chicks. Although it is aesthetically unpleasant, IMD is an acceptable and humane method of chick disposal providing the equipment has been well maintained and used responsibly.

It is essential the flow of birds into the apparatus is slow enough to avoid the equipment jamming, birds rebounding from the blades or birds suffocating prior to maceration.

For further information on the use of IMD devises see the HSA’s Code of Practice for the Disposal of Chicks in Hatcheries Code-of-practice-for-the-killing-of-chicks-in-hatcheries-jan-2023.pdf and technical note on IMDs .


Young chicks may also be killed using anoxic gas mixtures. Chicks could be placed in to a pre-filled gas chamber. Alternatively they could be placed in to an open chamber which is then sealed and gas added when all chicks are in position. The latter is preferable from a welfare perspective as it allows gentler handling of the conscious birds and a more gradual introduction of gas mixture.

Gas mixtures can be:

  • 90% argon (or other inert gas) and a maximum of 2% total oxygen by volume (2% total oxygen by volume is the proportion of oxygen in a 90% argon, 10% air mixture, as the amount of oxygen in air is 20.9%).
  • a maximum of 30% carbon dioxide and a minimum of 60% argon (or other inert gas) with no more than 2% total oxygen by volume
  • the highest possible concentration of carbon dioxide from a source of 100%                  (not recommended by the HSA due to the aversiveness of high concentrations of CO2).

It must be noted that when anoxic gas mixtures are used for the euthanasia of day-old chicks the residual oxygen concentration is critical. This must be kept below 2% and exposure to the gas mixture must be for long enough to ensure that all chicks are all killed effectively and as quickly and humanely as possible. The HSA recommends that residual oxygen level should not exceed 1%.

The minimum dwell times given in Table 6 below must be adhered to.

Table 6: Minimum dwell times for chicks, poults, ducklings and goslings.




3 Minutes

Turkey poults: sickly, injured or deformed

3 Minutes

Turkey poults: healthy

5 Minutes

Ducklings and goslings

5 Minutes


For further information regarding the use of gas to kill poultry chicks see the HSA technical notes Gas-killing-of-chicks-in-hatcheries.pdf

The HSA’s Code of Practice for the Killing of Chicks in Hatcheries 


Considerations when using IMD during depopulation due to disease control

IMD and gas can be used to kill a large number of young chicks quickly. IMD is preferred when possible as it results in immediate death. Both methods however required specialised equipment and macerated tissues and contaminated blades may present a biosecurity and human health and safety risk.

Conclusion – species and situations

Gas is suitable for killing day old poultry chicks, however care must be taken to ensure the appropriate concentration of gas is maintained. IMD is suitable for killing day old poultry chicks and embryonated eggs.

Next: Carcase disposal

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