One technical problem was that during winter buried objects can get very cold, and it was possible the mine's electronics would get too cold to work after some days underground. Various methods to get around this were studied, such as wrapping the bombs in insulating blankets. One particularly remarkable proposal suggested that live chickens 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. Their body heat would, it seems, have been sufficient to keep the mine's 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."[4]​ @Curionic

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