I see. Couldn't you put the chicken wire on top of the foam? You might have to slather the mud on a bit thick but I think it might work. Or how about a light sanding with some fine grit sand paper (by hand of course)?
I have to check my mud from last year. It might be moldy and that would suck. Good thing I bought another big bucket.
Did I mention I'm also a Halloween packrat? I have been told I have an ace hardware in my garage. Now where's that sales clerk darn it!?! I can't find nothing!