An update from the chicken infirmary, Dumpling and Little seemed to have weathered the night separated from the rest of the flock just fine. When we checked on them this morning they had knocked their food and water over, Little had already laid an egg on the ground, and both were happy to see us.
We moved Dumpling back with the rest of the flock and Little didn't appear to mind being on her own now. The wound on her back looked to be healing well beyond what we expected, so we hope to have her moved back in with the other hens in a few days.
I let her out this afternoon to free range in the yard while I took care of some chores. That seemed to make her happy.
Like I said, she's spoiled.