Farm-raised pigs are dirty, smelly animals ... They're also an environmental hazard. Their manure contains phosphorus, which ... runs off into lakes ... depleting oxygen, killing fish, stimulating algae overgrowth and emitting greenhouse gases. ... Pigs provide more dietary protein, more cheaply, to more people than any other animal. ... Two Canadian scientists have created a pig whose manure doesn't contain very much phosphorus at all. ... The Enviropig is one of many new technologies that are putting environmentalists and organic-food proponents in a quandary: should they remain categorically opposed to genetically modified (GM) foods ... at the expense of...