I used to have ducks. Great animals. If you let nature take its course, they'd probably get eaten by a wild animal. My ducks were only outdoors (but stayed in a pen during the night) and never flew away. They had their own kiddie pool that they loved to splash in. The only flaw about having ducks is that they're very messy. They poop everywhere and they have very gross poop lol. My ducks ate chicken scratch, I think it was, as well as lettuce, snails, and earthworms (which they loooved). I'm so glad you're kind enough to rescue some of these wonderful animals. If your parents aren't ready to set up a pen for them maybe you should give them to the guy you said you know who can take care of them. I'm sure that they would love to step in or splash in some shallow water, such as in a kiddie pool, even though they've never seen water before. Ducks take to water pretty naturally. Good luck!! Keep us updated on what you decide to do and what happens with the ducks.