egg incubating

My duck has started laying some eggs, at first i couldn't find them but yesterday I noticed the one of my old chicken hens is sitting on them.  As neither the ducks or the chicken has ever raised young before, I am a bit worried that any chicks emerging might be killed, has anyone any advice?  I am not in possesion of an incubator at the moment but plan on getting one soon.

My duck has started laying some eggs, at first i couldn't find them but yesterday I noticed the one of my old chicken hens is sitting on them.  As neither the ducks or the chicken has ever raised young before, I am a bit worried that any chicks emerging might be killed, has anyone any advice?  I am not in possesion of an incubator at the moment but plan on getting one soon.

Hello Hamisbyrne
If she's sat tight seperate her and the eggs she's sitting off to one side out of the way of other fowl and preferably in a small enclosed coop big enough for her, situated on the ground, you can make a little nest for her comfort and to keep the eggs from rolling out of contact.
The earth will supply the humidity required.
Remove her morning and evening for food and water and allow her to dust bath, if she's a good sitter she will want to get straight back at it.
You can then use the incubator as back up should she get bored.

Shaving the beaks will make them look a little more like chickens and also cut down on the food bills