better picture
View attachment 1248343
It's hard to see (always hard to get good pictures of shiny egg yolks, lol). Here are some pictures you can compare yours to, and maybe crack another egg to confirm.
Fertile:

Not fertile:

Or, just put them in your incubator and see what happens. Worst case, they don't develop and no harm is done. Best case, they do develop and you hatch some ducklings
