By Colleen Jenkins

(Reuters) - Two former Republican presidential candidates are encouraging people to eat at Chick-fil-A on Wednesday to show support for the chain restaurant as it weathers criticism for its president's public opposition to same-sex marriage.

Dubbing the effort "Chick-fil-A Appreciation Day," ex-candidates Mike Huckabee and Rick Santorum said supporters would send a message about "traditional values" by eating a meal at one of the privately owned chain's more than 1,600 locations.

"The goal is simple: Let's affirm a business that operates on Christian principles and whose executives are willing to take a stand for the Godly values we espouse by simply showing up and eating at Chick-fil-A," Huckabee, a former Arkansas governor, said on his website.

Chick-fil-A, known for its chicken sandwiches and waffle fries and for being closed on Sundays, came under fire after its president, Dan Cathy, told an online religious newspaper that he supports "the biblical definition of the family unit" and that supporters of gay marriage were "arrogant."

Gay marriage supporters have responded by boycotting the chain and seeking to block new Chick-fil-As from opening.

Same-sex couples around the country plan a kiss-in at Chick-fil-A restaurants on Friday.

The general manager of New Hampshire's only Chick-fil-A franchise has reacted to the controversy by becoming a sponsor of the state's gay pride festival slated for August 11.

The restaurant in a Nashua shopping mall "has gay employees and serves gay customers with honor, dignity and respect," general manager Anthony Picolia said in a statement released by the organizers of New Hampshire Pride Fest.

"I would challenge people to come have a conversation with me before they make assumptions or boycott my restaurant," he said.

(This story is corrected with spelling of Chick-fil-a in headline)

(Additional reporting by Jason McLure; Editing by Paul Thomasch and Vicki Allen)