Bow-legged duckling, what to do?

I recently acquired 4 Pekin ducklings from someone who mail-ordered them but then couldn't keep them.  I was told they are 2 weeks old.  One of them is very bow-legged & I need to know what to do for him.  He has a very wide stance, as if he just got off a horse he'd been riding all afternoon.  His legs from hip to hock are at a 45 degree angle to his body, then his lower legs from hock to foot are at a 90 degree angle to the ground.  So far he doesn't seem to lag behind the others when walking around. 

I began giving them all some Poly-vi-sol vitamin drops as soon as I got them home, a few drops in the AM & the PM.  They're eating Purina Flock Raiser.  No photos are available to post, sorry.

Is this a good course of care?  Is there anything else I could give, to the bow-legged duckling & also to the others?  Thank you for your imput.

What material would you suggest for securing the legs in place?  Do you think gauze strips would work?  I am keeping them outside in a covered pen during the day & bring them into a straw-lined bin at night.  And where do you get capsules of powdered Niacin?  I could only find tablets & think it would be a bother to grind them up.  I'm giving them Poly-vi-sol baby vitamins (without iron) and that has niacin in it.

I'm afraid that my duck didn't have a good end.  I don't know where these particular ducklings came from, but they seemed to be weak stock.  I don't know if some Pekins are just meant for meat and aren't bred for long & healthy lives.  Perhaps you can start a new thread and post pictures of your duck and its issues, others on this duck forum may be able to give you better advice,