Mother Nature Network: Fair Oaks Farms in Indiana loves its manure. The farm has about 30,000 milk cows which produce more than a fair amount of manure every day. Several years ago the farm started putting that manure to good use, using it to power its barns and other structures. Now, according to a report in The New York Times, it is taking the manure one step further. Fair Oaks now converts some of its manure into enough compressed natural gas (CNG) to keep its fleet of 42 tractor-trailers on the road every day. "As...