The increasing size and complexity of road vehicles used for the transport of day-old chicks has raised concerns about the thermal environment achieved by the ventilation systems, within the load space of such transporters. To address the lack of scientific information available concerning such designs, given the high cost of these vehicles, CFD modelling would seem a viable option. This paper presents the comparison of full scale experimental and CFD model results concerning the air flow with and without heat load in the load space of one particular vehicle. The results show that CFD modelling can predict the mean ventilation flows successfully, but experimental turbulence levels are not reproduced. The numerical results are also sensitive to the boundary conditions assumed for the air conditioning system, making commercial implementation of methods of this type for design purposes potentially problematic at this time.