Physical conditions and mortalities associated with international air transport of young chicks

Transport conditions and mortalities of day-old breeding chicks associated with eight shipments from central Iowa to Asia were delineated. The chicks were shipped in commercial cardboard shipping containers with the dimensions of 61 L X 46 W X 18 H cm and 88 chicks/ container. The chicks were delivered by bus from the hatchery to the originating airports and from the receiving airports to the destination farms. During air transport, the chicks were situated in the cargo compartment of commercial passenger aircrafts. Transport time consisted of 13 to 18 h of flying time, 27 to 57 h of ground operation, 42 to 72 h in total journey. Both dead-on-arrival and the first seven-day mortality were found to be proportional to transport duration. Relative humidity inside the chick containers averaged 44% at 33 degrees C on the ground, but only 19% at 31 degrees C during flight. Container temperatures declined from 35 degrees C to 28 degrees C in 100 min during departure and increased from 28 degrees to 38 degrees C in 75 min during arrival. Stressful temperatures of 37 degrees C or higher averaged 4.5 h during the journey and tended to occur around departure and following arrival. However, no apparent functional relationship was detectable between the stressful temperature period and chick loss. Air temperature inside the container averaged 9 degrees and 4 degrees C warmer than the ambient during flight and ground operation, respectively. Air-exchange rates through the containers were estimated to be 3.67 and 9.03 m3.h-1.kg-1 during flight and ground operation, respectively. These air-exchange rates exceeded the literature recommended minimum ventilation rates for air transport of chickens. Barometric pressure averaged 100 kPa on the ground and 84 kPa during flight. The results suggested that under the present transport conditions, efforts should be made to limit transport time within 45 h to alleviate excess mortalities. Furthermore, an improved shipping container needs to be investigated to overcome adverse transport conditions.