Chicken ReIntegration

We have a flock of 7 hens. One of them injured her leg so we had to separate her while she healed. She is pretty well now, she still hobbles but I think this is as good as her leg will get. The problem now is that when we try to put her back with the other chickens 2 of them attack her relentlessly, one time they drew blood from her upper back. At this point she isn't defending herself against them so we've tried many things to get them to recognize her.
We tried putting her in at night to roost with them, this is when they pecked her the worst.
We have tried bringing other chickens out with her to free range and as long as it is not the two most aggressive ones that is fine but when we let all the chickens back in the other two still attack her.
We've tried isolating the two most aggressive ones, even having them sleep out of the coop overnight but they still seem to think the other chicken is the outsider.
We've also tried hanging a cabbage in the run to distract them and give them something to peck at but they prefer to peck at the chicken.

We had the injured chicken in a dog crate inside and near the coop while she was recovering so it's not like they weren't seeing her. They already had an established pecking order so I'm not sure why they are treating her like a new chicken.

Does anyone have any other suggestions? Perhaps we are not trying these methods long enough. This has been going on close to a month now and we are getting frustrated and sad at the thought that we are going to have to give away one of our chickens. Thanks for your thoughts.

Ana