Chicken wire is a mesh fencing used, traditionally, to confine poultry. Composed of galvanized wire, it holds up well to the elements. When digging on old home sites, you'll often unearth some that was used decades ago on the property.
Besides durability, chicken wire boasts flexibility and is easy to cut. It can be more difficult to cut and install types fencing with much heavier gauges.
Although it takes its name from its traditional use in poultry raising, we now use chicken wire in landscaping in many ways. For instance, chicken wire can be used to reinforce concrete. Folks with a bent for crafts make chicken-wire Christmas balls by rolling chicken wire into a ball and attaching Christmas lights to it.
But a more widespread use for chicken wire in landscaping is in organic pest control measures. Most commonly, chicken wire is used as fencing to encircle a garden area, thereby keeping out pests that would eat your plants. However, to keep out pests that can dig, note that you have to bury a portion of the chicken wire, as I detail in my article on rabbit-proof fences.
The hexagonal gaps in chicken wire range from 1/2 inch to 2 inches. If you are trying to keep out rodents as small as meadow mice, it's best to select the 1/2-inch type of chicken wire.
Besides enclosing gardens with chicken wire, people also encircle individual shrubs with it, as winter protection against pests. Just drive 3 or 4 stakes into the ground around the shrub to build a framework, then unroll the chicken wire across the outside of this framework. The unrolling will go easier if you stabilize one end of the chicken wire first by fastening it to one of the stakes, using twist ties.
But chicken wire isn't always installed vertically. I have found 2 uses for chicken wire that involve a horizontal installation: