Hi, there. Sorry to hear your duckling is feeling unwell. Hopefully, we can be of help. Would you mind answering a few questions?
Is the duckling producing frequent poops, if yes, could you post a picture? What kind of feed is being offered? What kind of bedding are you using? Do you have a picture of what they're being kept in? Is there a water dish, that allows the duckling to flush out her nares? Is the bird drinking? How does her crop area feel (pouch on the bird's chest right-side).
Was she just nibbling on the bedding, or did she actually ingest the piece?
If she actually ingested the piece, my main concern would be that she has a blockage somewhere in her digestive tract. A blockage is serious and needs to be dealt with the upmost care. If you live near a vet, I would suggest taking her there.
If you can't take her to a vet I can suggest a very basic treatment for blockage in the GI tract, but it's not guaranteed to work.
That basic treatment would include giving her a stool softener such as Metacuil, or a laxative like Dulcolax. I would personally suggest using Metamucil. To give her the Metamucil, simply mix it in with some water, or Gatorade until it slightly thick consistency, and suck some up into a syringe or eyedropper, and drip a few drops alongside her bill, being careful not aspirate her. Do this a couple of times a day.
In addition, to the above, I would start weighing her on a food scale so we can track her weight, and start adding electrolytes into her water to keep her hydrated. As with adding anything into a bird's water, always provide a clean water source in case they don't like the medicated stuff.