The others may be power grooming her then. It's basically when they pin her and groom her with some force. Generally they wind up 'clipping' the fur in the process, so it's almost like a haircut. You could try separating her out to be sure that this is indeed the problem, but if she seems happy with them and not too bothered by the scabs, then I wouldn't worry about it. The scabs most likely won't get infected, and rats are such fast little healers that they'll heal over before they really have a chance to even get infected. You can use a small dab of antibiotic ointment like polysporin or Neosporin on the worse of the scabs, but it's not really necessary.
It could also be that their playing is a little rough, and she's getting the brunt of it since she's the Low Man on the totem pole. Again, though, if she's happy, it's not bothering her all that much. If she was avoiding her cagemates, hiding from them, or seemed genuinely afraid, it'd be different.
ETA : itching and scratching is more of a constant, start/stop type of thing when it's related to mites. Just like when you get a bug bite, the itch can be so bad that you'll stop in mid conversation in order to really scratch it. She would be showing signs like running around then coming to a dead halt just to scratch. Normal grooming is different.
It could also be that their playing is a little rough, and she's getting the brunt of it since she's the Low Man on the totem pole. Again, though, if she's happy, it's not bothering her all that much. If she was avoiding her cagemates, hiding from them, or seemed genuinely afraid, it'd be different.
ETA : itching and scratching is more of a constant, start/stop type of thing when it's related to mites. Just like when you get a bug bite, the itch can be so bad that you'll stop in mid conversation in order to really scratch it. She would be showing signs like running around then coming to a dead halt just to scratch. Normal grooming is different.