By Jennifer Piacenti The Bills are still the SI Sportsbook Super Bowl favorites, while the Eagles now have the best odds among NFC teams. As we head into Week 5 of the NFL season, only one team remains undefeated and it’s not the Chiefs, Buccaneers, Bills or Packers – it’s the Eagles. Just like we drew it up, right? Meanwhile, the reigning AFC champion Bengals are off to a mediocre 2-2 start and the Chiefs and Bills look ready for another AFC postseason shootout. The reigning Super Bowl champion Rams have been lackluster offensively in their 2-2 start, as have the Bucs and the Packers to start…