Call duck sitting on eggs do I need to candle them to check for bad eggs?

[Duckiemomxx]

We’re on day 8 of pretty much constant sitting on eggs & she was on and off a few days before that- she’s on 16 eggs so I’m certain she wouldn’t of been sitting on some of them in time. Should I candle them? If so best way how to move her she’s aggressive if anyone goes near by. Or am I supposed to leave her to it but if I do that what happens if there’s a bad egg?
First time with a sitting ducky so all advice welcome xx thanks xx

 

[lost-duckling]

my scovies kick out the bad eggs on their own

 

[Duckiemomxx]

my scovies kick out the bad eggs on their own

Momma duck just left the eggs for a just snack and drink so I shut the eggs off and had a fast look we’ve got 9 fertile & growing nicely 2 no growth so removed & the rest were chicken eggs haha someone’s been laying in the wrong box, she’s back on them now so hopefully I haven’t disturbed her too much