you also have to remember that the aliens are still there and they need to defend themselves. it is a tv show and a little artistic license needs to be given. you have already given in to the fact that aliens have invaded, is it that far of a stretch to say that food sources are hard to come by due to the invasion? we have never been invaded by alines on such a large scale9that we know of...lol). how do you know that they have not destroyed all of the livestock. the fuel would most likely still be in the tanks, but how do you get it out with all the electricity plants being destroyed? the aliens have said they have studied our planet for centuries, they know our what will cripple us. how do you shoot something when it is reloading if it does not have to reload and has armor that our conventional bullets cannot penetrate? imagination goes along way. the fact that we cannot say for sure what an alien invasion would be like, including what weapons they may have or what supplies they may target is part of the allure of such a show. i enjoy it. i allow for some some inconsistencies because we do not/cannot know what would truly happen. if you don't like this kind of show because it is not 100% accurate, don't watch it. it's as simple as that. i enjoy letting my mind wander, in enjoy seeing what kind of things others can come up with to challenge the human race. it may make me a better survivor should it ever happen. and yes, i think that someone in the vast universe, there has to be another intelligent species, at least every bit as developed as humans. probably more.

you also have to remember that most houses have already been looted. i've seen looters first hand(tornado survivor in 85), it don't take long for the good stuff to disappear. people are hiding and hoarding. there would def. be a "i've found it, it's mine, get the hell out of here" attitude. if you can even find the other survivors hiding places.

also remember that the aliens have flying patrols that can spot large heat signatures such as those given off by motors. again, a stretch, but not so far outside the realm of possibility that it cannot be bought into.