A worrying five per cent can take as long as 15 minutes to die by suffocation.
UPC reports that the US approved using the method in cases of outbreaks of disease in November 2006.
But The Washington Post reports that the only approved method of euthanasia for egg-laying hens is by exposure to carbon dioxide gas, which puts the birds to sleep before killing them.
7
Dead chickens strewn across the floor of the warehouse after the foam suffocation
7
Foam is poured on top of the chickens as they attempt to scramble to safety
7
Gallons of foam is poured on top of the chickens to suffocate them
The method most commonly used for turkeys and broiler chickens involves the use of a water-based foam, which kills the birds within approximately one minute.
The above footage was said to have been filmed in Israel in 2014, where the practice is allowed.