Why are all the pig farms exploding?Annalee Newitz12/03/13 1:35pm284EditPromoteDismissUndismissHideGo to permalinkIt sounds like a factory farm legend. One day, the manure collected under the floorboards of a pig barn starts foaming uncontrollably. Then, the foam releases gas that explodes. In one incident — all too real — over 1,500 pigs were killed, and one human seriously injured. What's going on?