Principles of Design Strong metal frame lined with solid hardwood sides. Vertical metal bars should be bolted in place at entry and exit with sliding or hinged wooden doors to the exterior of the bars. The upper third of the wooden doors must have ventilation spaces or openings. IATA specifies that the roof must be solid over the animal's head and slatted over the loin and hindquarters for ventilation. For ground transportation, however, removable panels or hinged doors over the animal's head can be useful in administering to medical needs and monitoring the animal.
Hatches also allow for more ventilation when an animal is standing calmly.
The interior must be smooth with no projections. Entry and exit doors must be closed and bolted in strategic places to be strong enough to resist the animal. The container must be constructed in such a way that the floor and lower sides are leak-proof. Dimensions must be large enough to prevent cramping without allowing unnecessary movement. Only nuts and bolts should be used in the container.