abnormal body shape

I purchased 6 straight run indian runner ducklings off of craigslist this spring, they were hatched on mother's day from a mallard runner drake, a fawn hen and a blue hen. It looks like we had 3 males and 3 females judging by the tail curl. Lots of different colors! I found it hard to voice sex...

We have a 17 week old pullet (americana) that hops rather than runs, looks a bit deformed in wing and body shape. Otherwise she's fine, no respiratory or other symptoms. No signs of bumblefoot or other infections. No changes in eyes, no true paralyzed body parts... is mareks progressive or...