Free range traditionally means poultry are not fenced in or the fence boundaries are so large that it does not affect the birds movement. Ranging requires a fair amount of land. Allowing poultry to roam freely can make managing your birds more difficult.
Normally, free range birds are fed minimal feed and instead are allowed to feed off the land. This does not allow for consistent nutrition or diet for the birds. Because birds are exposed to a greater variation of weather conditions than housed poultry, the level of performance is reduced (Plamondon, 2003). Disease control is also more challenging to owners who allow free range. Birds may come in contact with wildfowl, which tend to be carriers of avian diseases.
The greatest concern is predators. With birds roaming free, there is no protection provided. Domestic poultry make easy targets for predators because many domestic poultry species are no longer fully flighted. Many birds allowed to roam free disappear and never return home - they are killed by wild animals, are picked up by someone, or are incorporated into another person's flock. You have no idea where the birds are traveling or if they will return home at the end of the day.