Caring for ducklings

First time duck owner here, I've had them about a year, and 2 of the more trusting ones have become broody.  They should be hatching any day now.  
Just wondering, I mean a lot of chick/duckling care information is usually what you do with them if they don't have their mother present, because you incubated or purchased them....if they Do have their mother to bring them up, what are the important things we need to provide for them?  

- Protection from predators at night and preferably during the day too (I'm not sure how we're going to provide continuous daytime protection if allowing them to learn to forage with their mother....is it best just to keep them enclosed so you don't lose them? I was thinking of trying to let them out hopefully for a limited time supervised walk around then put them back in)
- How much space should they have?  
- If the fenced off space keeps them in but isn't high enough for the mother, will she leave to forage etc & come back or just stay with them the whole time? (We've just cobbled together some very low chicken wire we had surrounding a - what we call a ute but in America I think you call a 'truck' canopy, if you know what that is, a low thing with windows that open)
- Some (how much?) duckling appropriate feed
- A shallow pool during the day time (should that be all day or supervised swims then taken away because they can get too cold or drown sometimes?)

TIA for your advice :)

I have never had ducks so I found these threads that might answer your questions:

https://permies.com/t/37721/Ducks-Safe-Fed-Affordably

https://permies.com/t/190051/protecting-free-range-ducks-night

I hope our duck experts will chime in.

Hi Jonie,
I must also admit my experience does not cover ducks, but there was another thread asking about resources for raising ducks, and I think that also would have some good info.  https://permies.com/t/268985/Books-resources-raising-ducks-meat

One piece I threw in was the "Duck Chronicles" by Jack Spirko. It was a series of short videos following ducklings from post office to full grown. He talks about and shows how he raised them.

This should be the watch list. https://www.youtube.com/watch?v=2F1YJi-6ygk&list=PLpHUZsnFSzdLq6vPE3MaDpBrUzvyhrpbm

We have a big flock of ducks in a high predator zone close to a wilderness area. We overnight them in a centralized fenced off 'duck village'. We then drive (herd by foot, not automobile) them around to a different daytime location and drive them back to their village before nightfall. Ducks can see 360 degrees around them and will always be the first to spot arial predators. As long as there are trees or bushes, they can avoid arial predators easily. If they are young, you can run string or twine lines above them to discourage arial predators.

Land based predators are a different story. Most predator issues are at night. We keep them locked up at night in houses. Foxes, coyotes, neighborhood dogs, and bears are kept at bay via a portable electric netting fence where ever they are working in the daytime. We let the ducks roam freely without electric fence in the spring muck season and after it snows in the fall. With snow, we can see predator tracks if they are around and if they are aroud, we keep them safe in their village until the predators move on.

Over the years we've lost more ducks to natural health problems than to predators.

We feed them 1/3 lb of soy-free layer pellets each along with a big helping communal sprouted grains each day. Ducks belong in water, and they need water to eat. As long as they can get in and out of the water, there should be no safety issues. For young ducks, you can bury a three gallon feed bowl into the ground so they can get in and out.