Bumping this thread rather than start another on the same topic.
I have 3 runner ducks that I picked up free on CL. They don't lay, and so haven't been terribly useful to us, other than the fact that they are super cute and we love watching them waddle and forage.
There is a ditch around the property (we're out in farmland no neighbors in view) and I've started to think that it might be really useful to us to give them access to the ditch and surrounding area to let them forage for the grassy weeds (mostly foxtail) that grows there and eventually makes trouble for out little dogs. My hope is that they will keep the grasses in check and hopefully cut their feeding bill some. The neighboring farms are lemon orchards, so I don't think they'll cause any crop damage.
But: will they leave us? I know they view their little yard as home, so I feel like they will return to the duck house if they feel unsafe. But I just was worried they may wander too far.
What are peoples experience with this? Do they tend to stay close to home?
I'm not sure how long ago you got your runners, but if it's recently, they will probably wait till they settle in before laying.
Regarding letting them range. Ducks eat greens as part of a larger diet. They will eat grass and weeds, but I wouldn't depend on them (especially if you only have 3) to keep your weeds under control. What they will get in those weeds are probably a lot of yummy bugs, and that will keep your feed bill down. However, whenever you let ducks range outside of their safe zone, you are risking their safety. They are prey animals and don't have a lot in the way of defenses. If they view their yard as safe, then yes, runners will come back. My flock has 60 acres to range, use only about 6 of that unless I entice them further by feeding in another location, but prefer to spend their downtime in their fenced yard.