Egg binding can be helped sometimes with a long swim in lukewarm water.
There are some other serious problems that can cause those symptoms. I don't want to worry you, but I have a duck who had similar symptoms this week and right now she's at the vet hospital getting fluids and antibiotics. Her kidneys are having trouble.
But there are a number of things that can cause leg problems - bumblefoot, other infections, toxicity, worms . . . do you have a vet? Something you can do in any case is get her into a warmer environment (85F), quiet, clean, and give her vitamins and whatever food you can get her to eat.
Is she eating, by the way?