Sorry to hear Elsa's having problems.
Could you post a few more pictures of that "broken feather"?
It looks like it might be a broken pin feather, but its hard to tell from the photo shown. At least from the picture, it doesn't look too recent and I'd be surprised if it's the sole cause of her limp.
Could you post a video of her walking so we can an idea how bad her limp is? To post a video, you'll need to upload it a video platform like Youtube or Vimeo, then copy/paste the link here.
Besides the limp, is she exhibiting any symptoms, such as lethargy, not wanting to eat drink, etc? What is she being fed?
Odds are, she jumped off the perch and sprained her leg a little bit. The best thing for her at this point is rest, but there are something you can do, to alleviate some of her pain, and speed the process of healing. That might include soaking the leg, in epsom salts water for 15/20 minutes every few days, she may also benefit if you add one 325mg aspirin tablet in 250ml of her drinking water.
Very important you keep her nails trimmed, as once they become overgrown it can seriously affect their walking abilities, and can cause problems that you're seeing here.
In addition to that, you'll want to address what may have caused her limp, are you're perches to high in the coop, is the bedding to hard, etc? If you post some pictures of you're setup we may be able to detect any environmental issues that may predispose her to develop limp.