Abstract: A trailer for transporting live poultry hatchlings has a cargo space for containing a plurality of perforated hatching containers. The hatching containers are stacked to create a central passage for air flow along the length of the trailer from which the air is admitted into a side duct on each side of the trailer through apertures in each side wall of the cargo space. This creates a transverse flow of air through the hatchling containers. A variety of measures may be undertaken alone or in combination to promote a similar transverse flow of air at all positions along the length of the trailer. The size of the apertures, spacing between apertures, cross-sectional area of the side ducts, cross-sectional area of the cargo space, or a combination thereof, may be varied along the length of the trailer to promote a similar transverse flow of air at all positions along the length of the trailer.