Injured duck

[Ninaand moe]

Hi I have a 8 week old duck that has sustained leg injury’s.
Not sure what to do.
Eating and drinking fine.
Can not stand and when it tries it balances on its knee section and cries.
It happened about three days ago.

 

[Yardmom]

What is the normal diet for the duckling? Is it currently getting extra niacin or other supplements?