Google defines Pecking Order as such:
A hierarchy of status seen among members of a group of people or animals, originally as observed among hens (chickens).
My flock is pictured above in peace with an established pecking order.
This article will refer to chicken pecking orders specifically.
How, When, Where & Why:
The actual pecking order itself comes from nature. Past generations were able to produce viable offspring, which roam the Earth today. The reason we have the chickens we do today, is from the natural pecking order, the animal hierarchy, that was formed in relation to the survival of the fittest theory. As in, the weak and sickly chickens did not make it, only the best foragers, escape artists and overall survivalists were able to reproduce offspring, chickens with desirable traits were the final product.
We can see this often in nature, say with deer, any deer that doesn't have a thick fur coat will freeze in harsh winter, one that got bit by a predator will likely die from infection and one that couldn't eat enough bark or forage enough food would starve. Unfortunately this is how nature works, its simply the survival of the fittest. Today people will sometimes make the mistake of breeding a deformed chicken into their flock and allowing the disability to be mixed into the gene pool, weakening their flock in the long run. The problem can also be observed in deer with hunters only killing the biggest, healthiest deer which leads to my theory of are the weaker bucks possibly the best survivalists? If man, the hunter, only wants to hunt a buck with a healthy, large rack --the small, weak buck gets to away walk free. The problem with this is, that the weaker deer or the weaker chickens, aren't as prepared as a past generation was to adapt to change. Healthier animals are better prepared overall, while the weaker generations are more susceptible to natural predation.
The actual pecking and dominance occurs during a breeding season, a food shortage or an insecurity, such a new group of chickens or other animals. A head chicken, a leader, will want their flock to stay healthy and alive from the potential new threat(s). So the leader will assert their dominance if and whenever possible, whether on their own flock members to seem intimidating or to the newcomers to keep their dominance position, same with any of flock member seeing the potential threat. This goes back to the survival of the fittest concept, the leader of the flock eats first then whomever is next and so on, then the least dominant chicken is the most likely to starve. Funny thing with chickens though, they can graze together and all be kept well fed on a pasture even with a large group, because each chicken will forage for its own food. The behavior I mentioned can be observed with a tasty treat in a flock of chickens, with the head chicken ready to hurt anyone in their way for the treat.
Chickens have great memories, they can recognize their own pecking order and each chicken's face in their flock. Sometimes, even if a particular chicken knows they will get pecked by another, will deliberately try to change the pecking order to have a better chance at survival or to get the treat you're offering.
There can also be flocks within flocks. A second generation male will stand up to his father and try to take his spot as the alpha male, the dominant gene that will be produced. In some cases the second male will succeed (say his father submits due to age, then his father will just act as a submissive male) but in most cases the offspring will fail and will got off to start his own flock within the flock, where he has his own hen or two, known as his harem, and furthering his genes and his fathers because he shares half of the same DNA. Another trait that can be observed in flocks are the dominant females, the main companion of the flock leader, which can be flipped, there can be an alpha female with a companion male. This behavior can even be observed in an all female flock, where one female will be so dominant that she will try a half hearted crow.
In conclusion, referring to the totem pole reference, the weakest chicken carries all the weight of the flock aggression, while the chicken on top is free to do as they wish and peck anyone below them on a lower segment of the totem pole, a.k.a. the pecking order.
My flock keeps a peaceful pecking order, they take naps together and allow me to take pictures all the time.
Thank you for reading and please give credit if and when needed,
-Whittni (November 2012)
Feel free to ask/email me questions!