Well, the three little delinquents showed up this morning in time for breakfast. I suspect they spent the night under the shed. Although I looked under there last night as best I could, there are some areas that are hard to see. After everyone was out and about for a while, I happened to see three of the older ducks (that didn't disappear last night) coming out from under the shed, as if they'd been taking a tour or something... "oh yes, very nice, you say this is the family room?"... I wonder if they are checking out potential nesting sites.
Today I put up electronet to try to keep the ducks, chickens, and guineas confined to the back and keep them from coming across the front yard, and heading for the driveway and the neighbor's back yard. We'll see how well that works - I can't surround the whole back yard so if they go out of their way far enough, they can just walk around.