Taming / training is simple and repeatable. Fear of predators can be overcome very easily. See following links. Many of poor quality but still informative with respect to techniques that can be in taming / training. Birds are American games. Some hand reared and some hen reared.
https://www.backyardchickens.com/t/407880/ambassadors-for-the-farm
https://www.backyardchickens.com/t/407880/ambassadors-for-the-farm
