I was really freaked out when I got my first soft egg. So I did a lot of research. Im still a little freaked out, honestly.
It is usually attributed to lack of calcium. Sometimes the lack of it, sometimes the lack of ability to process it. Sometimes lack of other nutrients, bad diet, lack of sunshine blah blah blah the list goes on. Sometimes, it is a genetic flaw.
My ducks get A LOT of calcium, in various forms. they get a layer feed with added calcium, they get crushed egg shell sprinkled over their food sometimes, they get Oystershell served ala carte, free choice and They get lots of snails and pill bugs, that are pure calcium. (the reason I got ducks was to manage the burgeoning snail population!) Lots of other goodies like meal worms, greens, fruits & vegie scraps, and PEAS every morning. So in short (LOL) nutrition is not the problem. They have their own pond and buckets of fresh water every 15 feet wherever they roam so water isnt an issue and their pen is very open air so lots of sunshine, they are out in the yard and splashing in their pond 12 hours a day on average, so .......... That pretty much leaves genetic flaw.
Im keeping an eye on things but if they dont start laying some decent eggs I have to chalk it up to bad genes and will be contacting the breeder I got them from.
They are very healthy and active ducks, so Im not worried about that. but I did not get them for pets.
I got them for bug controll and to provide breakfast and dinner.