Just seconds before Governor appeared in front of prison gates Tyreeese showed Rick and Daryl a mutilated rat. Clearly it wasn't doing of Carol. Also someone fed rats to the walkers in the earlier episode. We saw also a walker with spring trap in her leg when Carl and Hershel went to woods to collect berries. What might it hint at? I get the feeling that producers of the Walking Dead do this on purpose to create some kind of "mysterious enemy". Could it be the hunters? Or someone going crazy? Bob? Lizzie? I am interested to hear your theoires/opinions.