You did the right thing
Releasing a duck is alot different than releasing a deer or a hog. Ducks are natural foragers and Im sure she can find some reeds or leaves to bed down in. I would keep placing feed out though near the pond. I have a few rescued ducks that were once wild and are now happily domesticated. Sure, in the morning they yell to be put out like little brats but by 8 pm they make their way back into their night time yard, not help needed.
![smile.png](https://www.backyardchickens.com/img/smilies/smile.png)