The chickens would be sealed inside the casing, with a supply of food and water; they would remain alive for a week or so. Their body heat would, it seems, have been sufficient to keep the mine's components at a working temperature.Why a seven-tonne 10-kiloton nuclear landmine? To save Germany from Soviet invasion by rendering large parts of it uninhabitable with fallout.
Supposedly the mines were never deployed, and BLUE PEACOCK was cancelled in 1958 when Whitehall realised that German popular opinion would not look kindly upon a British plan to
One can only hope that the chooks do not join forces with the Canaries in the Coal Mines, who have been breeding down there, and will one day find their way back to the surface -- flightless, blind, and very very angry.