Watch her closely and give her supportive care. If she does not seem to be getting any better I might be concerned about Mareks disease as flockwatccher mentioned. Limping and pupil changes can be associated with the disease. You mentioned she was vaccinated but sadly about 10% of vaccinated birds can still get mareks. Sometimes what happens is the chick will get vaccinated but won't be given ample time to develop antibodies immunity before being exposed. Ideally once the chick is vaccinated it should remain indoors for the very least 14 days some say longer to give the chick time to develop the antibodies before exposure.exposure would be out doors and adult chickens. If the chick is not given that time they can still catch the Mareks disease before the antibodies had time to give immunity..so newly vaccinated chick's should be given that time to develop the antibodies before they are allowed outside and around adult birds. many times they are not given time for the antibodies to build in their system and they are exposed too soon. This causes vaccine failure because the bird was exposed before it had time to build resistance.. also the vaccine itself isn't 100% effective sadly. I'm not saying she has mareks I'm just saying be aware that it could be possible. Espically if after supportive care and some time given for healing if she does not heal or show improvents at that point I might consider looking into mareks disease. I wish you the best and hope she heals quickly. I hope this helps and God bless.