When my SF had a torn tendon she would use her wing to balance herself and would use her wings and sometimes feet to scoot herself around.The chick is about 2 and a half weeks. It was fine at first. It was one of the most active chick. one morning it just lay there in a corner. I came back to see it in the same spot. I separated him from the others but it kept calling for his buddies. I put him back. He eats and drinks water. He moves about using the wings as support. Not sure if it has an injured leg. I checked and the leg looks fine externally. Its been 3 days so far. idno what to do about it.