CK called to report that all of the boys were in the same field. Hrm. We diagnosed this problem as Loki breaking a fence, and two independent gate failures. Wow, what a string of bad luck.
But no one was severely injured, and no one broke out of the external perimeter. So while it was slightly nerve-wracking, especially when we went out there and all of the big boys were lying down (is someone lame? is someone's leg broken?), it turned out that everyone was ok and nothing was permanently harmed in the process. We put Loki and Lerris back into the dog yard with a rigged fence-fix for the night, re-sorted Scout and the little boys, and turned out the lights. We hoped that the lights out would stop Loki from beating on the fence until I could get out in the morning with more semi-permanent repairs.
ETA: Which it did. I fixed the fence on Monday morning with more chains and clips. It should hold for a few more weeks.