Hi again Goat_Walker. As your grief abates a bit, you will come up with solutions that work for you, so don't fret too much right now. Just keep them locked up until they have recovered from their shock and you have a chance to work out what you're going to do.
Some options to consider when you're ready:
Option One: Keep the dogs locked up. I know it's probably not your decision to make, but you might discuss with your family the option of fencing a play area for the dogs so that you can continue to let your ducks free range. Keep in mind that free ranging ducks will *always* have occasional losses. It's the nature of running loose. But you can significantly limit the losses by controlling your known predators (in your case, the family dogs). In my case, all of my daytime losses have been to dogs and unfortunately I am still dealing with the situation because they don't belong to me and animal control here is slow to do much unless they catch an animal in the act. But that is another story and situation for another thread (and yes, I'm still taking measures in hopes of eventually resolving the situation entirely).
Option Two: Extend the duck pen, add a swimming pool inside of it, and keep the ducks locked all the time.
Option Three: Use a triplex run as described in Holderread's Guide to Raising Ducks--the house where they sleep at night, an outdoor gravel/sand/straw/whatever run that is kept clean but bedded, and a second outdoor run that is planted with grass, shrubs, and whatever else you want in there, and where they are allowed to roam only when the weather is dry and the plants in good condition. This arrangement allows the ducks some of the benefits of free-ranging within a limited amount of highly protected space.
Bottom line is, you may still experience losses. Unfortunately, it's the nature of life and of raising poultry in particular. But I'm sure you will find ways to limit the losses.
In the mean time, take the time to grieve for your loss. Many people don't understand how much it's possible to love a bird or birds, so don't be too hard on them when they don't understand your grief. We understand.
And, by the way, I hope your others make it home. I would not be surprised if they do--a frightened waterbird will often hide in the woods or elsewhere for a couple days before returning cautiously home. They will be afraid to return to the "scene of the crime" at first, and they are VERY good at hiding when they're motivated to do so. I especially hope Monty makes it. My oldest son is named Monty.