MONTPELIER, Vt. (AP) -- Federal immigration officials are cracking down on Vermont dairy farmers as part of a national effort, asking them to provide records to prove their workers are legal.

Kelly Loftus, a spokeswoman for the state Agency of Agriculture, said immigration officials visited four farms on Thursday.

In an "emergency notice to all dairy farmers in the northeast," a Vermont group called Dairy Farmers Working Together said that up to 100 Vermont dairy farmers have been served with subpoenas seeking payroll records from November 2008 to November 2009.

Loftus said the move creates another level of anxiety and ...