I agree with Kevin. I have moved a nest successfully but it wasn't easy and I was very lucky to have a very committed momma duck. I don't ever want to have to do that again. I remove eggs all the time! Just try to pull some of the eggs when she's gone off for her bath and poop. Then quickly candle and first take any that look "different". Last August I had a Rouen trying to sit on 32. I removed eggs until she was back to I think it was 18, then eventually removed about 6 more. Your duck won't like you messing with her eggs if she's right there, but if you do it while she's away, it should not be an issue. She hasn't passed kindergarten and she can't count!
ETA: you might consider posting your questions over on The Broody Duck Thread (if you have not already) -- lots of experienced helpful hatchers over there too.