Actually, when the neighbors ducks would come over and get in the garden, they never ate any of it. But they would get the bugs off the leaves and the ground. I don' t think they would bother it.
Dixygirl----I have mine in a 6x6 dog kennel and each day I will move it to a different area, then I will rake up the grass because it will be laid flat. I also put down a little DE to help control the fly population. Also the ducks will be let out several times a day while I am there to supervise.
I don't know if you were kidding about the vent sexing but I have to tell you I had to go try it. LOL!
If I did it right and who knows, but I think my pekin is female, I have one ruen female and 1 one ruen male (they are all two weeks old) and my cayuga is five weeks and I could not find certain parts on her (oh please) without her totally stressing out. The cayuga carries on like I am killing it when I take it out the pen and it is loud. I also noticed the face is taking on a pretty green sheen.
they forage by grass and bugs. they can get bugs by putting their beaks down in the mud and filtering with their beaks to get the bugs if you have never seen this wet down some dirt or grass so it is soft and watch them it is so funny.