Duckling can't poop

[Dunkin Ducks]

One of my ducklings is seeming to be having a lot of trouble. When he was hatching the mom threw him out of the nest but after a few hours I placed him back in the nest, he hatched just fine. He's clearly the runt though since he's so much smaller than the others. They're all only 3 days old now. Today I noticed he looked really bloated. I looked at his vent and it was crusted over a bit, I cleaned it up and gave him a warm bath. I noticed he's breathing heavy and I can literally hear his heart beating from 2 feet away. He won't drink anything either. He did poop once now that I've had him sitting with me. I brought another duckling to keep him company & we're just listening to soft music and I'm petting him. I don't know what to do for him, any ideas??

The photos are of his vent after I gave him the bath. It looks all red and puffy

 

[Miss Lydia]

@Dunkin Ducks How's your lil duckling this morning?

 

[casportpony]

Welcome to BYC and so sorry your little duckling is ill.

That looks like his umbilicus and not his vent. It's quite possible that he has what is called "mushy chick disease" which is an infection of the yolk sac. It's been my experience that chicks and ducklings with this disease are very hard to save.

Do you have a vet? If so, call them and ask if it would be possible to treat this. You might also find this link helpful:
http://www.poultrydvm.com/condition/chick-yolk-sac-infection-omphalitis