Your ducks are still pretty young for laying, so I doubt there's anything wrong. Our young duck was hatched around mid-May, and started laying a few weeks ago (and has only missed an egg one day since - she's a real machine); however, I think she's an exception - I spoke with her breeder and his other young ducks of about the same age hadn't started laying yet. Did I read somewhere you have Ancona's? They're a little bigger than Magpies, which might mean they're a little slower to mature too. And with the days being so short, it is likely they won't start laying until we at least turn the corner on the daylight hours. But I've only had ducks since May, so my experience is pretty limited.
We have 2 young drakes, a young duck, and a duck (1+ yrs old). I've decided one of the drakes has to go since too often the two drakes try to mate with the young duck at the same time and I'm afraid with both of them holding her down she might drown.
Bummer about you ending up with so many drakes.
Hopefully you'll get some nice ducklings out of them in Spring to give you some more ducks/hens.