I appreciate the help. I'm at a loss, because I feel like I've tried everything (vet visit, checked for mites countless times, Banixx, warm epsom salt baths (not with OPEN wounds), and Vaseline on lesions, but not Neosporin- I will have to try that). The fact that the other chickens have had absolutely no problems whatsoever also has me confused, and the fact that the injured chicken lays good eggs, as I would assume her egg production would be noticeably affected by a lack of vitamins. She has been acting more like herself the last few hours, laying in the sun and has enough energy to run (to join the other chickens around the yard). I keep a fairly close eye on her, and she doesn't seem to be picking at herself enough to cause severe feather loss (except for the last few days that she has been picking at the sore spots on her wings). She seems like a very happy, unbothered chicken (aside from the last few days), so I still have no clue how to narrow down my search of the causes of her feather loss. The previous owner (distant relative) got her as a few-month-old chick, but I believe she has had (minimal) bald spots since they originally came in.