Female ducks can live peacefully with chickens as long as you keep these things in mind:
-Ducks are only harder to keep than chickens in that they are MESSY!
-They also need access to water they can fully submerge there heads in at all times, in order to keep their eyes, nostrils, and bills clean.
-They can eat hen food as long as they recieve supplemental niacin in the form of brewer's yeast, crushed tablets, or liquid niacin.
-The coop will need extra high maintinence to keep it dry enough for chickens, as duck poo is extremely watery and plentiful. -Ducks also should have access to swiming or bathing water at least every other day in a kiddie pool, stock tank, or backyard pond of sorts.
-Ducklings can be raised with chicks as long as the ducks' nutritional needs are met, all waterers are kept clean, and the bedding is kept dry enough to accomodate the chickens.
(I probably missed a few things, but I'm sure someone else will add to my list.)
If you do decide to get ducks for looks, some of the most beautiful breeds for females are:
Welsh harlequin
Saxony
Cayuga
Swedish
Ancona
All of these are docile, hardy, beautiful, and good layers to boot.
Good luck!