Development of an on farm anoxic gas foam delivery system


DEFRA (and Animal Health as their operational partner) have a requirement for in-situ emergency killing of poultry flocks in the event of a notifiable disease outbreak. Whole House Gassing (WHG, where birds are killed in their production housing) is the currently preferred option, particularly when there is a risk to human health.  However not all poultry buildings are suitable for WHG due to the fact they cannot be adequately sealed. 

An innovative alternative system of whole house gassing has been developed which uses a high expansion water based foam to deliver an anoxic gas (nitrogen) into poultry sheds.   In previous projects, a small scale system was constructed to allow laboratory studies to be conducted to assess the efficacy of anoxic as a humane method for whole house killing of poultry.  The findings showed that gas delivery with high expansion nitrogen filled foam is a humane method for the emergency killing of broilers and hens, and a report on parallel work conducted by the WUR Animal Science Group in the Netherlands (funded by the Dutch government) confirmed that it was also suitable for ducks and turkeys.  In further work a larger system was developed to successfully apply gas filled foam to groups of broilers.  This work determined the behaviour of the foam in larger areas and resulted in an operational protocol.

The aim of the project is to develop a fully mobile, full scale, on farm system to apply anoxic gas foam.  An initial phase will involve design of all the elements required to produce a system capable of working at a commercial scale, based on detailed information on the required flow rates, distribution and operational protocols generated in previous work.  This design will be associated with an accurate cost estimate, and based on the outcome of a review meeting, we will build and assemble a fully functional system.  The system will be subject to a series of detailed engineering tests to determine its performance under commercially relevant conditions including different types of poultry housing systems.  Finally, the system will be applied in trials with broilers, hens and turkeys to assess its effectiveness, reliability and welfare consequences.  Throughout the project, stakeholder meetings will be held to involve key poultry industry partners and the project outcomes will be disseminated fully to the industry. Successful completion of this work will therefore extend the capabilities of containing disease outbreaks as rapidly as possible and make available both dedicated equipment and a detailed protocol for this purpose.

The project will also help to determine the feasibility of gas foam as a method of humane killing of spent laying hens, broiler and turkey breeders at the end of lay in their poultry houses, which may have welfare advantages.