Need help with new duckling

[Platinumsky]

We just hatched some ducklings a few days ago from eggs in our incubator, it's been over a decade since I last raised ducks and I'm concerned about something stuck to the vent of the runt of the litter. It doesn't seem like regular feces, it looks darker and doesn't dissolve with a paper towel like I would expect. The little guy is still just as energetic as their siblings but I'm worried.

Image:
https://photos.app.goo.gl/geUNQ6XUpdv5watn6

 

[Miss Lydia]

Can the little duckling poop? you may need to soak the bottom and see if it will come off that way. Nice warm water.