Maybe you can arrange for her to live next to the other chickens, able to see and interact through a wire mesh divider but not able to be picked on.
That would keep her from getting too lonely, and would let the others get used to seeing her and not picking on her.
If you just put her in with the others, she might have a very tough time until she grows up.
If you let them out to free range, you could probably let her out too, because free ranging would give enough space for her to avoid the big chickens if needed. But she might need a separate space in the coop & run until she's fully mature and able to make her way into the pecking order safely. (When a pullet starts to lay eggs, the change in her hormones can also change her behavior in ways that let her fit in better with other adult chickens.)
Sometimes you can arrange a safe place with a small entrance, so the pullet can go in but the other chickens cannot. But that works better with really small chicks. The bigger they get, the less possible that is, and she might already be too big for that to work.