RALEIGH, N.C. (AP) - Trials that could alter the operations and profitability of eastern North Carolina's hog farms and pork industry will start in April.

U.S. District Judge W. Earl Britt said Monday that deciding lawsuits filed by more than 500 neighbors of industrial-scale hog operations will begin with two test cases. The neighbors contend waste smells, noise and clouds of flies caused by tens of thousands of animals create intense nuisances.

An initial trial will involve eight to 10 households with similar complaints. The second case will focus on the experience of a single household. Lawyers for livestock company Murphy-Brown say that's needed to understand potential liability.

The litigation by often-poor neighbors represents one of the biggest legal and financial threats to pork producers since industrial-scale hog farming took off a generation ago.