A judge in Marquette County has refused to overturn a state policy making it illegal to possess exotic swine.
The Michigan Department of Natural Resources last year banned ownership of animals known as wild boar, feral swine or razorbacks. Officials say they're escaping from hunting preserves, reproducing and wreaking havoc in woods and farm fields.
The DNR estimates that thousands are running loose.
Farmers and ranchers in northern Michigan are challenging the order in five separate lawsuits. They say their hogs aren't escaping and they're being unfairly targeted.
They asked Circuit Judge Thomas Solka to throw out the policy as unconstitutionally vague.
Solka rejected the request in a ruling Monday. But he says the lawsuits can continue because the hog owners can still fight the DNR policy on other grounds.