Most of you know the indestructible shutters that protect gun stores, malls and some other shops from zombies and survivors alike. I think that chain link fences, the military fence in LV as well as fancy metal fences around mansions should behave similarity.
Instead of just standing on the other side and barely acknowledging your presence, zombies should walk it to them and try to tear them down. They shouldn’t be able to break them, or at least not easily, but just imagine the scenery of dozens of zombies pressing against the other side of the fence.
(Also please make metal doors and gates more resistant)