Ducks will lay quite happily without the amorous intentions of a handsome male. The eggs a duck lays without the help of a drake are not fertilised and will therefore never hatch.
Should you have a male duck, you can be sure he will do his best to fertilise the eggs. If a duck is broody she will then sit on these eggs for 28 days (the incubation period) and with a bit of luck these eggs will hatch and produce more ducks. It is very exciting to breed ducks but you should consider what you are going to do with any offspring if you don' t have space to keep them. It is also worth bearing in mind that if you rear more males then these will fight in the breeding season.