Also, in the first scenes of the show you see empty tanks and such.
How did a bunch of slow mindless zombies beat a tank?
How can a bunch of relatively untrained people survive, when the highly trained military shooters where all over run.
anyways... ya I know suspend reality and all.
The guys in the tank were probably bitten at some point. I'd assume it ran out of ammo and gas.
The military had men with machine guns but were over run due to sheer numbers.
The current cast survived by being a small and mobile unit. The people on the farm were simply in a remote enough location to be relatively safe.

