PITTSFORD, N.Y. -- A daily review of the hot topics coming out of Buffalo Bills training camp:

• Thunderstorms in the area caused a rain delay about in hour into practice. That lasted about an hour before players came back onto the field to complete the full-length session. Players were in full pads for the seventh consecutive practice, highlighting what has been a physical training camp for the Bills. It will be interesting to see if coach Doug Marrone dials it back at all in the final two practices before the preseason opener in Canton, Ohio.

• The offensive line carousel continued to spin Wednesday with Chris Hairston leaving practice with a back injury. Hairston had been in the mix at right guard, where there is an open competition that includes incumbent Kraig Urbik. That battle added another participant Wednesday when fifth-round rookie Cyril Richardson received some reps with the first team. Urbik continues to get the majority of reps in team drills, but for a player whom the Bills signed to a four-year extension in 2012, he can't feel comfortable lining up alongside younger players on the second team, as he did at one point Wednesday.

• The Bills have picked up the pace in the red zone. Marrone has implemented a 7-on-7 period at the end of practice dedicated to red-zone work, and results were impressive Wednesday. Although it was against the second-team defense, EJ Manuel completed four touchdowns in his five reps. Two went to Robert Woods, and tight ends Chris Gragg (returning from a week-long absence) and Lee Smith snagged the others. Jeff Tuel then stepped in and completed his first two passes for touchdowns. With some success in the 7-on-7 look, it might be time for Marrone to switch to an 11-on-11 drill and add a pass-rush element for Manuel to face in the red zone.

• Tight end Scott Chandler (groin) remained out of practice for a second straight day, as did tight end Tony Moeaki (hamstring). Their injuries don't appear to be serious, but it has thinned the position for practices. The key for both players -- Moeaki especially, given his injury history -- will be to stay healthy once the regular season begins.

• Chris Hogan continues to get significant playing time with the first-team offense and has become a reliable player in the slot. The Bills got in some 11-on-11 third-down work Wednesday and Hogan cut across the middle of the field for Manuel's biggest gain of the drill. Secondary coach Donnie Henderson, always vocal from behind the play, made it a point for his safeties to keep an eye out for No. 15.