So the Bulls aren't completely immune to laying an egg, but it's still very rare. And though they've managed to handle similar circumstances better in the past few weeks, it's still on a back-to-back on the road in front of a comparably-good team. The Hawks played the night before as well, but still: though (as Jay pointed out) Sam Smith may not recognize it yet, they are a good defensive team, currently 5th in the NBA.
And Atlanta had a couple important matchups to take advantage of Saturday night, both stemming from an athleticism and quickness gap. The frontcourt of Horford and Smith did a lot of damage in attacking Carlos Boozer, and as a team Atlanta completely owned the rebounding edge (32% ORR, 84% DRR).
At PG they also had an edge with a multi-headed attack of Jeff Teague and Lou Williams, the latter starting for the first time this season. Hinrich was probably given too long of a leash when it was apparent all he could really do defensively was foul, though the Bulls smaller guards didn't fare much better. And though the Bulls tried to use a more traditional SG to get a size edge on the other end, it had very sporadic results and thus ended up as a net negative.
The Hawks started the game out just as sloppily as Chicago, but a huge 36-16 second quarter was powered by those advantages plus a 3-pointer run by one Kyle Korver (who finished with 13 points on 8 shots). Stacey King was hoping all night that Luol Deng would be part of the Bulls advantage on the wings, but though he started the game fairly hot he finished 5-14. After the game Deng admitted his shoulder (injured the night prior in New York) was bothering him and led him to avoid contact. And indeed, Deng took just 5 of his 14 attempts in the paint, and only had a single free-throw.
The Hawks were able to go small with Teague/Williams, yet also had a big lineup at times with Josh Smith moving to the SF spot alongside Horford and Zaza Pachulia, both looks giving the Bulls trouble for different reasons. Luckily things got so out of hand that even Tom Thibodeau showed reason in pulling the plug early, as no starter played in the 4th quarter, and later Taj Gibson was given a rest himself on a likely still-sore ankle. It was only the second time this season the Bulls were in a laugher of a defeat, so I'm comfortable in saying they earned the rest.