Just in case you think you have to keep them separate, you don't have to. Ducks and chickens can co-exist happily together, and ducks do not carry any sicknessess that might pass onto your chickens. Ducks do not get sick as easily as chickens. In fact, they rarely get sick at all. Their body temperatures are much higher than chickens' and bacteria often cannot survive in ducks. They do need a pool, but the chickens will probably not try to get in or drown.
You can keep them separate, if you want to, but that will be much more expensive than keeping them with your chickens. Ducks also need brewers yeast, you can buy it on amazon. They can eat chicken layer, duck feed can be hard to find.
I am getting ducks myself (blue swedish) and cannot wait! I have read up a lot on ducks, but don't know really much more that I could say to help you. I will tag some people who can probably help more.
@DuckPro (since you went over to the duck-side

)
@chickens really
@The Moonshiner
@Ravynscroft
All of these people seem to know a lot about ducks.