Don’t massage her crop again because they can choke to death. You can massage an impacted crop, but never a puffy or sour crop. Refrigerate a tsp of the coconut oil and then chop it into small pieces. Usually chickens will peck and eat them. Get some Monistat (miconazole) cream at your pharmacy...
It takes time to figure out what is going on sometimes. The bare spot on her back looks like feather picking by others. It is possible they know she feels bad and are picking on her, but also look for overcrowding, boredom, and too little protein in the diet.
Can you feel of her crop and tell...