Does my duck seem sick?

[New duck mommy 2021]

She was for awhile, but it didn’t cure her infection. It did help though.
We don’t know. The vet says they can’t find the infection for us, so we plan to go to another vet that sees duck sometime this month.
We did, but we don’t anymore. We’re trying to find an unflavored calcium since flavored ones aren’t good for her.

She needs calcium to lay eggs
Crushed oyster shells are good for them
My ducks get them in a separate bowl all day long
This helps to prevent egg bound , soft shells eggs ect
I would definitely grab her some
I would also get durvet liquid calcium and give her 1 ml through syringe or over a small treat. It says injectable for cattle but for birds it’s oral
This helps them when they are egg bound or really low on calcium
Shouldn’t be used as a substitute for crushed oyster shells just as needed for issues
It can be bought at ts or Amazon
Could her mow belly be that she has an egg stuck in there ? When did she lay last ?