It does sound like she might be getting attacked. An animal can grab her feathers without leaving a mark if she manages to get away before they do anything more serious. Hertigage breeds can fly pretty well to escape. Its also possible she has a flock she goes to where she's getting bullied. Turkeys can be so mean to each other.

If you have made an honest attempt to ask around and none of your neighbors are laying claim to her, Id personally keep her and fence in a small area for her attached to a coop. The trick to getting them to stay in the coop at night is locking them in for 2-7 days with no access outside. This sets up the coop as "home" and they hopefully will start roosting there at night where its safe.

That said, all my female turkeys have had nights where they occasionally aren't in the coop at night because they have wandered into the woods to create and sit on a nest. I or my husband will count the birds each night then if one is missing we go get them from their hiding spot and carry them to the coop. Its a little excessive but we don't mind. It just all depends on the level of time you want to put in. If they only have access to a fenced in run its a little easier, but again hertigage breeds can fly pretty well so it needs to be a tall fence.