The Eagles host the Buffalo Bills with the return of LeSean McCoy, the Eagles all-time leading rusher who was traded in the offseason. McCoy's started well mentally and physically, as he kissed the Eagles logo and embraced Eagles owner Jeffrey Lurie, as well as racking up 63 yards on 12 carries. After halftime, he started to fall apart. McCoy only rushed for 8 carries and 11 yards in the 2nd half, and after the game, he was not on the field to interact with his former teammates and did not shake hands with coach Kelly, which McCoy said he wouldn't do prior to Week 14. The game started off well for Philly, besides a first down rush by McCoy, the Buffalo offense was forced to punt after 5 plays, and on the ensuing drive, Darren Sproles rushed for 15 yards to put his team on the 1 yard line, then ran it in for a TD on the next play. The Bills answered with a Tyrod Taylor pass ro Sammy Watkins, a catch and run that went 47 yards for a TD. After several more drives, the Eagles strike again in the second quarter, with first rounder Nelson Agholor getting his first career touchdown on a 53-yard catch and run. The Bills could only muster a Dan Carpenter field goal, which was countered by a Caleb Sturgis field goal with 5 seconds left in the half. The second half started with a Caleb Sturgis field goal, but the Bills scored 10 unanswered points, then intercepted Sam Bradford on the ensuing drive. The score stayed 20-20 until the fourth quarter, where Sturgis kicked another field goal with 3 minutes left. The Bills started to gain some momentum, but a rushed pass led to an interception by backup safety Ed Reynolds clinching the game for the Eagles. With the win, the Eagles improved to 6-7, but remained in second place in the NFC East due to a win by the Redskins.. How many yards of difference were there between LeSean McCoy's yards per carry value in the first two quarters when compared against the last two qyarters?