It may seem odd in these times to organize Foie Gras Week to celebrate this most luxurious, and controversial, of ingredients. Especially in Philadelphia, where animal-rights activists waged a nasty battle to get the overfattened duck liver off restaurant menus.

Starting tomorrow, more than 18 restaurants will add at least one $5 foie-gras dish to their menus through next Thursday.

Odd, maybe, but Foie Gras Week is not intended as a traffic-builder, said Mackenzie Hilton, executive chef at Mercato in Washington Square West.

It's to make a point. "As chefs, we're not going to back down," she said. "It's about our rights to choose, as chefs, what we serve."

It also may have something to do with the deep discounts being offered by suppliers of some pricey ingredients.

While a similar Foie Gras Week a year and a half ago was a highly charged event as it played out against protests, no feathers will be flying this time when a group calling itself Chefs for Choice showcases an ingredient that detractors contend is inhumanely produced.

Just as the economy has cooled, so has the foie-gras protest climate. Activists opt for informational interviews with chefs instead of camping out on sidewalks and doorsteps.

The lead protest group Hugs for Puppies - which since has rebranded itself the Humane League of Philadelphia - no longer sees the efficiency of picketing, said Nick Cooney, its organizer. Its new pet cause is persuading colleges and other institutions to stop buying eggs from hens confined to tight cages.

Nationally, the move to ban foie gras is in retreat. Philadelphia Councilman Jack Kelly once drafted a bill to ban it, but the idea went nowhere. Chicago's council last year reversed a short-lived ban. "People seemed sick of even talking about it," writes journalist Mark Caro in his new book The Foie Gras Wars, which devotes three chapters to the Philadelphia protests. Terry McNally, owner of Fairmount's London Grill, obtained a court order to keep Cooney and company away.

And pragmatism has set in. What seemed luxurious to a chef not long ago - $36.50 a pound, at wholesale - has simply become a high-price ingredient.

Producers Hudson Valley Foie Gras and Rougié are deeply discounting foie gras to Chefs for Choice through local distributor Julius Silvert, said Hudson Valley manager Rick Bishop.

"We have Restaurant Week, Beer Week. I figured, why not Foie Gras Week," organizer Bernard Dehaene of the Society Hill restaurant Zot said.

Dehaene said the foie-gras industry had been unfairly portrayed as cruel. Hudson Valley, countering that it farms ducks humanely, will bring a consulting veterinarian to Philadelphia next week to talk to restaurant staffs about the farming process.

Chef Olivier de Saint Martin said he took foie gras off the menu at Caribou Cafe two years ago after repeated protests, though he cut a deal with Cooney to allow him to serve it on special occasions.

Saint Martin will serve foie gras this week at his two Center City restaurants - seared with an onion confit and Banyuls wine in puff pastry at Zinc, and seared with an asparagus vinaigrette at Caribou.

Foie gras (say it "fwah GRAH") is the engorged liver of a duck or goose force-fed by a process called gavage. To animal-rights activists, gavage is cruel.

One chef, David Ansill of Ansill in Queen Village, sighed when asked yesterday why he would not participate. "Foie gras got me in trouble," he said, referring to months of Hugs for Puppies picketing at his restaurant and home. "It was a minimal part of my menu anyway."