How bad is it? If you can splint it's legs and it can then get to food and water on it's own, I say give it a chance.

With newly hatched chicks (who are quite rubbery the first few days), you can make a shoe or splint for them to wear for a few days, which can help a surprising lot, sometimes even fixing the leg/foot completely. More info & how-to's here, scroll down to 'Making A Chick Splint':

http://jackshenhouse.com/VSChickHensBroodiesChicks.htm

If you DO have to euthanize it, see this page, all the way at the bottom:

http://jackshenhouse.com/VSChickHealth.htm

Velvet ~:>