I'd fence the boys off from her when you think she's close to hatching. Use hardware cloth or something similar that ducklings can't run through. I'm glad they're not chasing her off the nest to mate, actually. Chances are she'll raise her babies up just fine. If you provide starter crumble and a shallow pan of water in containers low-sided enough for ducklings, she'll take care of them just fine. As they get a little larger and more mobile, you can upgrade them to a dog dish with a brick inside and outside for climbing in and out, and then a little further on, give them a bathing pan (I use a cement mixing pan from the hardware store) with bricks stacked outside and some inside so babies can climb in and out. Mama will be glad to have a bath too. She can eat the baby food, it won't do her any harm and she'll likely be a little underweight after brooding eggs.
You'll need to keep back some more girls, two drakes to a hen leads to overmating and injury.
Your birds are pretty, you'll have to share photos when they hatch!
oh - bedding. can you work around her? And then offer her some clean straw to work into her nest? That's what I do. Maybe they tolerate more messing around, but I haven't wanted to risk running them off and making their nest look unfamiliar.
