Soft shells happen when ducks are just starting up too. You can offer kale chopped up which is another good source of calcium.
My ducks just acted off like she wasn't feeling good. I wasn't sure if she was egg bound but just to be on the safe side I brought her in and made her a nice bedroom in the downstairs bathroom let her soak in the tub in nice warm water off and on all day, she would drink but wouldn't eat. not even meal worms this was on a sat. Sunday morning she laid and egg it was normal in every way but she still wasn't acting right by night she died. I am not sure if she was internally laying or if she had an infection they hide illness from us so well they are about gone sometimes before you know their sick. This one was 2 when she died.
My older duck was 7 and had just about the same symptoms..
So sad about your 2 ducks I sure would be bummed if something like that happened. I remember hearing from someone that ducks are tough and make it had to tell something's wrong. Thank you for the kale tip - I'll try that.
JoeyLaDragonBoo is just a name my daughter cooked up, haha. I'm not up on kid's shows either; we live in the Ice Age and have no TV.