All instincts of a predator are inborn in GSD and Husky, probably they are revealed stronger than in any other breeds. By rolling in carrion the predator wants to mask himself for hunting, but it also stops other dogs biting him because carrion is poisonous, especially fish. Regarding the latter, it is more typical for males than for females to roll in dead meat, they fight more often.
If your dog rolls in fresh meat - it is only because she's unable to find dead, but, beware, she might find some dead sparrow and you will deal with all this stink which is pretty difficult to wash out. She feels unsure about something, possibly some other female threatens her. Not necessarily face to face, but by leaving her scent in the way of your daily walking route. She could be new to the area, big and strong - your dog recognises it solely by smell.