I have had ducks for 10 years and got Pilgrim geese this year. I integrated the goslings with the ducks as early as I could get them outside. As they have gotten older they don't hang out with the ducks during the day anymore but still go into the shed together at night and there haven't been...
You can always do tractors and electric netting to protect from most predators. We do that with our red broilers (because I can't stand to look at cx). It works very well for us.
Of course they get the garden rejects and scraps but I do have a seperate section that I call the animal garden. It is 25x50 and this year has sunflowers, dent corn, pumpkins, patty pan squash and field peas.
Welcome to BYC. I have considered starting a flock of Dorkings myself. I believe with good breeding stock you could have a nice sustaining meat & egg combo.