Sunday Night Football: Bills lead 49ers 21-3 at halftime

It's a snow game in Orchard Park, and the Bills have had a clear advantage playing in the elements, taking a 21-3 lead into halftime.While the 49ers scored first on a Jake Moody 33-yard field goal, Ray Davis took in a 5-yard touchdown at the end of the first quarter to put Buffalo ahead and the club has not looked back.James Cook had a 65-yard touchdown run midway through the second quarter, and Josh Allen connected with receiver Mack Hollins for a 7-yard touchdown with 41 seconds left in the half.Allen is 8-of-10 passing for 96 yards with a touchdown. He's also rushed for 10 yards on two attempts.Cook has 101 yards on nine carries.Buffalo has averaged 9.2 yards per play. The club had 238 yards in the first half, gaining 142 on total on the ground with an average of 8.9 yards per carry.While the 49ers have not looked comfortable or confident moving on the snow-covered turf, the bigger deal is that Christian McCaffrey exited the contest in the second quarter due to a knee injury. McCaffrey took a pitch to the right, took a few slow steps, and then slid down to give himself up. But he may have been injured a couple of plays before, when he was brought down by a shoe-string tackle on...