Help with baby chick, leg problems

Hi! My sister had this chick hatch and it cannot walk because its leg and toes are all curled up. At first she thought it was splay leg so we tried some splints, tape, etc but that didn’t seem to help. We have been drop feeding and watering her, and have also given selenium, vitamin E, and electrolytes. She eats decently well when fed, but she can’t walk over to food and water herself. She’s very energetic and vocal, she just doesn’t have the ability to move around and it’s heart breaking. She also doesn’t seem to be growing much — she is 5 days old and her siblings are much bigger than her. My sister has reached out to all the vets in our area and no one is willing/able to take a look, and we desperately want to help this baby.

If you have any advice at all, please comment! We would be so grateful, especially as we are still relatively new to having chickens. Obviously we know there is a chance that we will have to put her down but that is absolutely last resort. My sister views her chickens as pets and they are all very precious to her.