She went back to camp last night. She claims that there's nothing wrong; apparently, she didn't know that anyone suspected anything. She just thought that our parents were picking her up for her day off. We observed her behavior, and it was nothing out of the ordinary.
As for the part about eating, it was because the camp frequently serves chicken, something that Anne refuses to eat. We raised pheasants a few years ago, and ever since, she hasn't eaten poultry of any kind. And she talks, laughs, crys, etc in her sleep every night (she did that before she went to camp). It's just that she's sharing a room with several other staff members, and she keeps them up at night. It turned out that it was just the camp director overreacting. Everything is fine, thankfully.