Broody duck and eggs

My crested duck went broody about 29 and a half days ago. She started out with several eggs and now only has three (I guess she must have thinned the rest out as not being good). I expected a hatch yesterday and so far I am not seeing anything... the eggs would be a mix between a Roen and either crested, magpie, or buff. At what point should I check on the eggs by removing them from her? At what point do I lose hope that one will hatch? It’s driving me nuts?!

Ducklings can take a while to hatch. I would wait it out. Also some moms will leave the nest for a while each day and you can take the opportunity to candle the eggs and get rid of any bad ones.  Hope they start hatching soon!