First, the curled toe. Her mother likely had a vitamin-B deficiency when her egg was created. So the chick developed curled toes.
But that means it is very likely that the chick is deficient in some vitamins too. The standing issue could be because of the toes. But I would strongly suggest keeping her separate for a bit, and upping her protein. You can try Whey protein that they sell for people at Wal-mart. But I would go buy some mealworms, crickets, etc., and let her have those. You'll get a LOT more enjoyment out of watching her eat it, lol!
Although a vitamin supplement from Tractor Supply wouldn't hurt at all. But for the growth part, you really need lots of protein. If you have most of them on a grower feed, try putting her (and only her) back on a starter feed. It has a higher protein content. But you want to keep her separate to make sure SHE is getting the food, and the others aren't pushing her away from it, especially now that they are so much bigger.