Free-ranging chickens have access to a variety of foods that can provide them with the necessary nutrients they need. When chickens are allowed to free-range, they'll naturally forage for insects, worms, and other small animals in addition to eating grasses, greens, and other plants. These foods can be a good source of protein and other nutrients.
However, it's still important to make sure that free-ranging chickens receive a balanced diet. Many chicken keepers choose to supplement their chickens' diet with commercial feed, which is formulated to provide a balanced mix of protein, minerals, and vitamins. This can ensure that the chickens are getting all the essential nutrients they need to lay eggs, grow healthy feathers, and maintain overall health. Additionally, some chicken keepers may provide their free-ranging flock with additional supplements such as oyster shell for calcium or grit for digestion. It's always best to talk to a veterinarian or a poultry nutrition specialist to determine the appropriate diet for your chickens based on their individual needs.