Chicken cages in the strictest definition are merely containment systems designed for poultry. In large processing plants chickens are frequently housed in a very literal "cage". They have a small wire pen with a door that allows the birds to be placed inside or extracted from the cage as needed.
Some chicken cages are designed as carriers for chickens and other poultry. These can be made of wire or fashioned from thin strips of wood. The only purpose of a carrier cage is for transportation.
There are also larger chicken cages that are intended to be used as homes for flocks of these domesticated animals. In these instances a chicken cage can range from a simple A-frame structure of modest proportions to an elaborate chicken coop with a well defined housing structure and fenced, outdoor run.
The main purpose of these types of poultry cages is to give your flock of chickens a safe, healthy and comfortable place to live. A wooden structure will keep the birds safe from predators and bad weather. A fenced, outdoor run may or may not be included since many people allow their chickens to free range during the daylight hours.
Even a moveable structure such as a chicken tractor is termed a chicken cage by some people. These are chicken coops with wheels that allow the owner to move the flock of chickens to new terrain whenever needed.
You can find a number of plans that will outline the steps of building chicken cages. Many of these are very easy and the basic structure can be built in 1-2 days. Some of the larger, more complex chicken houses may require a week or more to build them correctly. You can even choose a cage or pen that comes with nesting boxes and special devices that will hold food and water for your chickens.
There are a number of different cages, coops, pens and roosting houses for chickens. These designs are available in so many styles that there is sure to be one that will be well suited for your yard or farm. If you are not handy with a hammer and screwdriver you might prefer to select one of the chicken cages that is already constructed.