No, I don't think they were pinched ducks. Why would you steal a flock of ducks only to then abandon them? I think it's far more likely that somebody bought them but then either hadn't realised how much work / mess they are, or that they had to move house and couldn't take them with them, so finding them a nice pond to live on probably sounded like a good idea.
Anyway, they're with us now. We were down to just three aged ducks, so we have plenty of room for more. We managed to catch them by putting feed into a wire gabion cage and then pulling a string to close the door when they were all in.
I'll get some better photos later, but here are a couple I took last night. We
think there's only one drake and all the rest are ducks. We also believe they're quite young, but what does everybody else think?
P.S. For the record, I think they're gorgeous!