Your ducks will need at least as much protection from predators as your chickens, possibly more, since they have little, if any ability to fly and they don't roost off the ground. They do need protection from airborn predators, as well, so you may need to cover the run they are in, at least with some kind of netting to prevent entry by raptors. Their night housing has to be secure from any potential predators in your area.
Ducks need a water source that allows them to dunk their heads at least up to their nostrils, so a nipple watering system or other controlled watering system will probably not work well for them. They do not HAVE to have swimming water, but they like it. A kiddie pool is adequate. Ducks are messy and generate mud, but unlike chickens, their poo is not "hot" and can go straight into garden soil without composting first.