Do you mean just hardware cloth on the top with the contained sitting in the middle of it? So the water just falls through?
Oops, yes this is what I meant. I did try cutting a hole in the middle and setting the bowl down in that but got annoying to clean.
As far as ducks trying to mate with chickens is concerned it hasn't been an issue for me ever. Other than some laughs when I let call ducks live with Langshans and the call ducks tried to mate with the hens...it really defied description.