What will happen to all them zombies after a while
 

remember the kid in the attic.
that might happen to all them zombiez

Nah, the kid in the attic died that way. He starved to death and turned after he died. Although it might be possible that the walkers will continue to rot until eventually their brain rots away as well, which could be considered them dying "of old age" if you look at it a certain way.

Yes I think that if a Walker doesn't feed it will starve, but it seems to takes much longer for them to starve than a living human. This was mentioned in the Talking Dead on AMC, because they are casting mostly very thin actors to play Walkers.

Also with the discovery that Walkers that lose their mouths and cannot eat actually become calm and just roam around, ignoring people until they starve to death., you can assume walkers will eventually decompose.

But that's the tv show and not the comics, but I'm pretty sure the starvation logic is the same...

So the world would then have only occasional zombies when someone dies? So, like a world with Gila Monsters (Venomous slow lizard) everywhere? That actually seems normal.

watch Torn Apart and thats what i always assumed what would eventually happen to all of them

when zombies eat they dont get nutrition from it, so they can't starve because they don't need to eat, they don't even need a stomach or intestines and the blood in their body isn't flowing to make their organs work, but then if i were to list every reason they don't need to eat, i would just be listing reasons why zombies are impossible, and that just spoils the fun ;)

Kirkman has said his zombies just keep rotting. So using that you can safely assume all zombies will eventually rot away over time and at some point the appocalypse will work itself out. In that case, shooting people in the head could almost become a funeral ritual. :P

^^ this
Eventually they just become immobile & rot away. I would immagine they rot quicker in warmer climates and more slowly in cooler ones. Im pretty sure they can also freeze in place in sub-zero temps, and become mobile again once thawed. Keep in mind, unless theres eventualy some cure or vacine everyone will turn upon death, so a post Z.A. society would have to adapt to that somehow.

The zombies probably don't need to 'eat' ,but the virus/bacteria or whatever it is probably needs to,so it makes the zombie eat. Like it needs live cells, that's why they don't eat other zombies or something.

I actually like that answer lol

i think there is something to that theory, because the "virus/bacteria or whatever" needs energy so consuming the host (rotting) is what it would do unless it had something else to consume like fresh meat

notice the difference between zombies and the kid, the zombies have a greenish color while the kid is greyish

The kid is still a zombie, only difference is that he died from starvation, so he became an ultra thin zombie.