Was there any traumatizing event in August that made them stop laying, like a predator attack or did you dare change from them beloved food brand to another one?
Ducks sometimes stop laying for no obvious reasons and then start-up the egg business again as if nothing has happened.
Agree with
@DuckyDonna give them some more time, days are getting longer on the northern hemisphere (you are on the northern hemisphere?) and they should start laying again soon.
It is actually very healthy for them to stop laying during the Winter. Their little bodies need breaks from time to time, producing eggs is really hard work.
