This blog is my theory on the nature of herds in the Walking Dead universe, and why Rick never had to worry about them reaching Alexandria. First off, I have to explain how the herd forms in the first place...
Formation[]
As we all know, Walkers are attracted and move towards noise. When a walker hears a noise, it naturally moves towards it, whether it be another Walker, a person, or even a helicopter. For example, say a car alarm is sounding, all the Walkers in the area naturally move towards this noise. Eventually the alarm stops, but already there is a small group of Walkers collected in the area. Without a furthur stimulation, the Walkers would probably stay around the same area. Say then, a few hours later a car drives through the area. The survivors inside easily drive around this small group of Biters, but nevertheless, the Walkers see and hear the car and begin to follow in the direction it went.
This demonstrates the second thing Walkers are attracted by- movement. Perhaps 7 out of 10 of the Walkers in this mini-herd see and follow the car. It logically follows that the other 3 follow the other 7, as they are moving and creating noise. Henc,e Walkers attract other Walkers.
They begin walking down the road, slowly collecting other sole Walkers along the way, increasing their number. As more and more Walkers are attracted to the group, they make more and more noise, causing yet more Walkers to become attracted to the group. With enough Biters are in the area, and given enough time- a large and dangerous group forms, all making noises by occasionally falling over or letting out an undead grunt. So we have our herd.
Walkers followed the noise of the helicopter in Season 2.
The Theory[]
Our herd moves across the largely deserted country. Eventually, the herd arrives at a large open space, such as a large field or a quarry. This is where, according to my theory, the herd no longer becomes dangerous, or at least much less dangerous than it was before. Due to the sheer number of Walkers in the herd at this point, the noise they create is' 'huge. Survivors half a mile away are able to hear the herd, and are easily able to avoid it. Animals frightened away by the sound, also avoid the area. The noise created by the herd is now far louder than say the noise of the passing of the car from earlier.
Now, obviously more Walkers are in the middle of the herd than at the edges of it. By this reasoning, the noise and movement created by the herd is loudest and most active in the middle. As previously explained, Walkers are attracted to noise and movement. So therefore, the Walkers on the edge of the herd are attracted into the middle, and as they move inwards, Walkers from the middle are pushed out onto the edges, creating a sinister undead convection current of sorts. The main fact here is:
The herd isn't going anywhere!
The only movement is from the edges to the middle, and vice versa. No exterior sound even comes close to the racket created by the large amounts of Biters in the middle. Over time, Walkers may fall over and be crushed, the area they cover may turn into a swamp due to the constant steps from the edges to the middle, the repeated bumping into one another weakens individual Walkers over time. Eventually, the herd implodes on itself. Some lucky Walkers on the edges may eventually disperse and become attracted to some other noise, but the vast majority of Walkers in the herd are either destroyed or too weak or beaten up to move. The herd destroys itself.
An example of Walkers getting too close.
Rick Never Had to Worry[]
By my theory, the Walkers in the herd would have stayed just where they were- in the Quarry. Sure, quite a few would have walked away when an opening appeared. But most of them couldn't have heard over the noise of the other Walkers in the herd, and even if they did, would have been attracted by the rest of the herd's noise within seconds. More Walkers pouring into the Quarry would have only kept them more securely in the Quarry and sped up the herd's demise. Rick's group massive attempts to lead the herd away was the only thing that would ever have moved the majority of the herd out of the Quarry.
I can't understand any way plausible that the entire herd would move out of the Quarry, and then magically make a beeline for Alexandria. Bad judgement from Rick, and illogical writing from Kirkman and Co.
Exceptions[]
Of course, I'm not saying that herds aren't dangerous. Anyone attempting to take on a large herd is going to loose, as Rick's group learnt the hard way in the first half of Season 6. I also admit that certain situations could cause the herd to split or move in a different direction, such as:
- Survivors engineering the herd for their own means, such as The Whisperers.
- Continued loud noise, such as a long firefight with multiple guns firing off at the same time.
- A very loud noise, for example an explosion or even an earthquake.