There is always a flip side.. and here it is..
I hatched out 6 chicks and put them in a 2 foot by 5 foot brooder. The day before they went into the brooder, 5 chicks came out of it.
The first 5 were very well behaved - and 2 of the chicks were a week older than the other 3. Had no problems.
Same setup, and the 6 chicks have been horrible. The 1st chick who hatched was pecking at the other ones as they were zipping. she actally reached thru one of the eggs, got hold of some feathers, and dragged the egg a few inches across the bator ( it was a little bit funny, but not). I had to move the first 4 to the brooder before the others hatched because they were trying to peck thru the eggs. When I added the last 2 to the broooder- the first 4 ran up and pecked the daylights out of them. I had to put them back in the bator for another 12 hours to keep them safe.
There was so much screaming and pecking and biting. I was quite worried. To me it didn't seem normal- I kept a watchful eye and after a few days, they calmed down. But I had 3 bullies, not just one.
I would just wait and see- go with your gut. If she seems to be overly aggressive, seperate her where she can see the others but can't attack. after a few hours, try letting her back in with the others. They will most likely learn to get along, but it takes time. You could put a stuffed animal in there, or something to climb on, or something to hide behind .