One thing I noticed in the last episode is that the zombies aren’t as lazy as they look because the lawns are all mowed and even the highway right of ways have been cut. Also at the end of the previous episode Rick is shown driving past a plowed and planted field.
Those .223 carbines they were using to kill zombies would have caused really messy head wounds at that range rather like JFK getting shot in Dallas. But at least it finally dawned on them to think “Hey, we’ve got all these guns and all these zombies …guns …zombies …guns …Hmmmm…”