At the center of the lawsuit, filed in Middlesex County Superior Court, is the use of the words "Animal Care Certified" in a logo on egg cartons.
Under agreements with the Federal Trade Commission and with the attorneys general in New Jersey, 15 other states and the District of Columbia, egg sellers were to stop using that logo by April 2006, Compassion's general counsel, Cheryl Leahy, said in an interview.
Compassion Over Killing said that United Egg Producers, which licensed use of the logo to egg producers meeting its standards, agreed to replace it with the words "United Egg Producers Certified."
The animal rights group had objected to the original wording, "Animal Care Certified," saying that implied to consumers that the eggs came from well-treated laying hens. But according to the group, the industry standard is to confine hens in stacks of metal cages with too little room to walk around, nest or perch.
As recently as Tuesday, the "Animal Care Certified" logo was on cartons of eggs from ISE America's nearly 1 million-bird New Jersey farm on sale in New Jersey, New York, Pennsylvania, Connecticut and Delaware, Leahy said.
"They're misleading consumers by putting this label on the carton ... when the real conditions are definitely cruel and abusive," she said.
The lawsuit alleges that logo violates the Consumer Fraud Act of New Jersey and also amounts to common law fraud under New Jersey law.
ISE America Vice President Greg Clanton said his company, a major East Coast egg supplier, removed the "Animal Care Certified" logo from its cartons in early 2006.
"We're not aware of any packaging issues," he said. "It looks like perhaps an old original print may have been reproduced at some time and was not detected."
Clanton said his company gets egg cartons from multiple manufacturers and is checking with them.
United Egg Producers said in a statement that it had not received the lawsuit.
"In the meantime, we are fully investigating this matter," it said.
Compassion Over Killing also sent letters to the attorneys general of New York and New Jersey late Wednesday, informing them of the lawsuit and asking them to take action against the defendants, Leahy said.
Jeff Lamm, a spokesman for New Jersey Attorney General Anne Milgram, said the office had not received the letter or lawsuit and so could not immediately say whether the defendants' actions violated their agreements.
"Once we get the documentation, we certainly will check into it," he said.
A spokesman for New York Attorney General Andrew Cuomo said all complaints are reviewed.
The Federal Trade Commission was reviewing the case and did not have an immediate comment.
