Especially in northern America, a long tradition has been to keep calves in individual outdoor hutches or to keep them in pens in a calf barn. It is an easy system to instruct employees and to observe calves. You see every time if a calf comes to drink milk, and calf health is easier to maintain when young animals are separated from each other. Due to the increase of automatic calf feeding systems, interest in group housing has also increased. Pressure from consumers to see calves raised in groups is also at play. How can we transition from single housing to group housing?