We have hawks here, and they´ll fight a chicken to get the chicks, but they tend not to take the adults. In my place I never see the hawks land, as I have geese. Geese are far too big for the hawks (the biggest we get are Carcará/Caracara and the White-tailed hawk). And the goslings are quite safe if they stay with the parents. Carcará are big enough, so whatever you get there to take a duck must be huge!I do have predator tape that I hung up around where the ducks hang out. I works if its sunny or windy but not if its cloudy. A hawk killed one of my ducks under a piece of it on a cloudy day.
I have heard of those chicken tractors. They sound like a good idea. Is it possible to make one or would I have to buy one? Where could I buy one? I have never seen one at my local Agway.
I use 1" weldmesh with broom handles pushed through the holes, then I wack them into the ground to make a temporary run. Then I put black plant shading over the top when they´re really small, and mine are fine like that. But maybe our hawks here aren´t as terrible as you have there?