I've always wondered that with zombie stuff where they've got an established base of operations. So many of them just use like, tall chain link fences and it's like why.
I forget the movie I'm thinking of exactly, it was a Romero one I'm sure. But the zombies learned to use weapons and whatnot, and they had somehow evolved to test weaknesses in their food's perimeter. So they just found the weak fence and pushed it over. XD