The first two must be from sisters because the moms look very similar. I believe that these are both second broods for those mothers.
This third family is at the two-week-old mark. The duckling at the front is a hybrid and if he survives, he will be a chunky-looking mallard.
Another duckling made it until he was three weeks old and disappeared. He was very independent and just old enough that he could have lived on his own, so I'm hoping he just went off somewhere and is hiding.