Blue Peacock—dubbed by the press the chicken-powered nuclear bomb—was the codename of a British tactical nuclear weapon project in the 1950s with the goal to store a number of ten-kiloton nuclear mines in Germany, to be placed at target locations on the North German Plain in the event of war. The mines would have been detonated by wire or an eight-day timer.
One technical problem was that buried objects—especially during winter—can get very cold, and it was possible the mine would not have worked after some days underground, due to the electronics being too cold to operate properly. One particularly remarkable proposal suggested that live chickens should be included in the mechanism. The chickens would be sealed inside the casing, with a supply of food and water; they would remain alive for a week or so. The body heat given off by the chickens would, it seems, have been sufficient to keep all the relevant components at a working temperature. This proposal was sufficiently outlandish that it was taken as an April Fool's Day joke when the Blue Peacock file was declassified on April 1, 2004. Tom O'Leary, head of education and interpretation at the National Archives, replied to the media that, "It does seem like an April Fool but it most certainly is not. The Civil Service does not do jokes."