It looks like she was pecked.
Clean that wound with mild soap and water, flush with saline or Vetericin spray, put antibiotic cream on it, and separate her from the other birds for now, (or they will keep pecking at it. It’s what they do.)
Make her a space of her own where she can still see and be seen by the others, but no one can get at her. Put food and water in her area.
Keep watch on the wound for infection. It should heal if you keep it clean and keep antibiotic cream on it.