70%cocoa :
Yes, that's right 
 Once the ducklings are old enough she will start to lose interest and go back to being 'her normal self'. 
It's great to have a hen who is a successful sitter and a good mother - you are lucky to have such a good hen 
 
Good on you for being willing to leave the ducklings with the hen 
 You'll have a wonderful time watching them as a little family. 
One thing I have found with mother hens is that they can kick litter into the waterer, so I put the waterer (I use a chick waterer) on a large piece of plywood to create a 'non litter' zone and this helps to keep the waterer clean. It can pay to have more than one waterer too, in slightly different spots. The ducklings won't be interested in water straight away though (maybe the day after they hatch) and they won't start to get hungry for food until about 48 hours after they hatch. 
Where is the hen now? Is she in her own separate area, protected from the other birds? It's a good idea to prevent the other birds from interacting with newly hatched ducklings or chicks (to keep the new babies safe).  
It's very exciting to have new ducklings!! I hope you get some sleep tonight.
We have a dog run that is always open in our fenced yard and a coop inside that so they all come and go as they please and she has the nest under the small coop that we bought. I tried moving here into a igloo dog house and she got mad.. I hope that since she is with the rest of the chickens and ducks this wont be a problem..