Now, obviously when it comes to unnatural things like Styrofoam or insulation, they are not so keen on what they can and can't eat. The one time I used my incubator (it's a hovabator or whatever they're called, made out of Styrofoam), I put it outside to be cleaned and the hens started to eat it! One corner has small, beak-sized chunks missing from them eating it!
Isn't that the truth. Have something obscure in the pen and watch them fall over each other to try it. They especially like my toes (and have blooded them before) ... Moral to that one is don't go into the coop with flip flops on.