Free range is a method of farming where the animals are allowed to roam freely instead of being contained in any manner.
The principle is to allow the animals as much freedom as possible, to live out their instinctual behaviours in a reasonably natural way. Free range, however does not necessarily mean that the products are cruelty-free or antibiotic-free, or that the animals spend the majority of their time outdoors.
The use of the term "free range" is only defined by the USDA for poultry production, and need only mean that the bird has had some access to the outdoors each day, which could be a dirty or concrete feedlot. USDA considers five minutes of open-air access each day to be adequate. Claims are defined by USDA, but are not verified by third party inspectors.