Size of calving box is

Size of the calving box is 100 - 150 sq ft.
A calf box or igloo is an effective accommodation system that helps you prevent contamination between calves and allows you to properly monitor feed consumption in the first few weeks after birth.
An individual loose box or stall used for calving should be 100 - 150 sqft and well-ventilated. Sufficient lighting is essential. It provided better protection to the cow and calf and avoids disturbances from other cows.