"Because there are no second chances on an empty stomach," the ad says.
It also encourages people to volunteer at a shelter on game day, perhaps even "hugging a homeless Pit Bull."
Vick served 18 months in prison for funding a dogfighting operation where pit bulls were killed.
In signing Vick to a two-year deal, the Eagles said he'd served his time and deserved a second chance.
"I think we're all getting tired of the 'Does he deserve a second chance?' kind of thing," said Bill Smith, founder and CEO of the shelter, which is near Valley Forge. "Maybe it's about time that the million pit bulls euthanized every year got their second chance."
"It's such a misunderstood breed. . . . They're great dogs," he said, adding they've gotten a terrible stigma "because of people like Michael Vick."
The ad's main aim is to bring attention back to the needs of dogs, he said.
"I think we just need to raise public awareness, and this is a good way to do that," he said.
"It may be funny. It may be clever. It may not," he said.
The ad will probably also run in other cities where the Eagles play, including San Diego, Chicago and New York, he said. Washington was first simply because the Post was running a special football preview section.
Smith, skeptical of Vick's newfound concern for pets, said that "if he had any sense of humor at all" and really wanted to help dogs, he could stand on the field before the Oct. 26 game and let players tackle him, so even more dogs will get fed.
"He should thank us" for the opportunity, he said.
Contact staff writer Peter Mucha at 215-854-4342 or firstname.lastname@example.org.