From the NY Times 5th Down blog:
Denver – 8-3 Despite Terrible Fumble Luck
The Broncos have won six straight games, and an easy remaining schedule sets them up for 12 or 13 wins. Amazingly, they’ve done this despite having terrible luck when it comes to recovering fumbles. Denver has forced 17 fumbles while coughing up 16. Once a ball is fumbled, it isn’t the better team that generally recovers the ball, it’s the team closest to the ball, and fumble recovery rates are notoriously random. Thirteen of Denver’s 16 fumbles were recovered by the defense, while the Broncos recovered only 5 of the 17 fumbles they forced. That means Denver has recovered just 24 percent (8 of 33) of the fumbles that have occurred in their games, making them as unfortunate as any team in the league. The good news for Broncos fans is that there is no reason to expect the Broncos’ poor fumble-recovery luck to continue, which makes them the rare 8-3 team that has arguably been unlucky.