Sometime large breeds like Pekin will pant and look over heated. The wheezing sounds worrisome but it maybe nothing too.Raspy makes me think drake. What are your outside temps?
Any other symptoms like drainage from nares. Are eyes clear? eating and drinking good? hanging with the others not laying around sleeping? If at all possible a video with the sound you're hearing? Tell us again their ages.
I'd say you have a little Blue Swedish duckling too. Don't see any Runners in there.
I know we're not on anything but breed but that feeder is way too small for those bills.
When they are standing do they stand up tall like a Runner? the one looks like maybe a Khaki Campbell [the brown one with the pretty markings coming in] The Black one maybe a Cayuga? If you can get pictures of them standing that would be great. The blue could be blue Swedish hard to say But they...
I think it’s a good idea to have 2 brooders ducks are so messy plus putting them on their own feed may help. Usually once you get them on the BComplex it doesn’t take long to see improvement 3 days to a week if it’s a niacin deficiency depends on how long they had it before starting on the...
How old is Whiskey now? I am sorry she is still having problems i hope the liquid B complex will help.
Here is info on how to give liquids
https://www.backyardchickens.com/articles/safely-administering-oral-medications-to-all-poultry-and-waterfowl.73335/
Bless it. Be sure that none of the other birds begin to bully the little one. Sometimes that can happen when one is showing signs of having a problem.
This will give you doses and info on Niacin deficiency and becasue it's so young you going to want to mush the mealworms a little so they are...
Make sure it's nutritional yeast and not baking yeast. Big difference. But when one is already has a problem liquid B complex is better.
https://www.backyardchickens.com/threads/feeding-ducklings-medicated-feed-the-myths-and-the-truth.1247838/
Info on liquid B complex and dose for age of...