Even though they have "leadership", I actually think Rick and Shane make very poor leaders.
Neither of the two delegate duties, responsibilities or any form of discipline to the others. They come up with plans on their own, barely bothering to receive any input from the rest of the group, and both are too emotional about one thing or another.
Personally, I would probably make a better leader than both of them which is probably why the story chooses to focus on one defunct group instead of, let's say, that group of 30 that Randall is from - Which, for all we know, could run a better (perhaps a bit more violent and aggressive) crew than Rick and Shane's.
Something I've learned is that no matter how well disciplined or how well trained a group may be - It's ultimate enemy will be idleness.
Since Rick and Shane fail to give the group purpose/motivation, everyone just kind've mills about - doing whatever.
They've been camping outside for the past week or so, and they haven't seen a zombie even come close to the fields. I think staying in one place for that amount of time with no recent incidences gave some people a false sense of security...
Also, the drama between the people in the group probably got their minds off the zombies as well...
I think Dale's death was a pretty good wake up call.
in all fairness, Dale was goingto die anyhow. main issue I have is Carl wandering off site first and teasing the walker brought him to the farm.... not telling anyone he did something wrong is a typicle kid action.... how old is he supposed to be anyhow?
I know I was thinking to myself why is Dale going that far away!? If I was him and I would have heard that cow, I would have been running back to the barn to tell the others I think a cow is dead over there. Not go over for a closer look.
But Dale was like 60 something years old and Sophia was 9, 10? And I think he had a gun with him? He probably thought if he seen something he could handle himself.