Maybe it is some sort of supply and demand thing.

In the early days of the zombie apocalypse, it must have been just like paradise to the zeehs. Brains everywhere, human flesh in large quantities. Now, humans are a rare ressource, the zeehs have to increase their efforts to get a grip on their favorite six feet happy meal. Hunting down a human and being able to start chewing his innards are two different things, especially if Mr. Z is kindly reminded by a larger group of zeehs of their prior clams.

Therefor, our little starving friend might be quite fond to start a hunting party of his own ... which might have led to the army that is now attacking the colony. Obviously, Randy is one of the smarter zeehs.

Just my 2ct.