Effect of stocking density and crate height on the welfare of fattening rabbits during transport to the slaughterhouse under mild Mediterranean summer conditions.

Recommendations by the European Food Safety Authority (EFSA) for rabbit transport propose sufficient floor space for all animals to adopt ventral recumbency with the possibility to change position, and a minimum crate height allowing rabbits to sit upright without their ears touching the ceiling. However, because of the scarcity of studies evaluating the effects of stocking density and crate height on rabbit welfare during transport, these recommendations were largely based on planimetric estimations and theoretical assumptions rather than empirical welfare outcomes. For rabbits weighing 2.0-2.5 kg, EFSA proposed a stocking density of approximately 47-50 kg/m2, whereas commercial stocking densities in the European Union typically range from 60 to 90 kg/m2, with approximately 70 kg/m2 being the most common. Similarly, EFSA recommended a minimum crate height of 35 cm, while commercial crates are generally 20-30 cm high. Therefore, this study aimed to characterise truck microclimatic conditions and evaluate the welfare implications of these recommendations under commercial transport conditions during mild Mediterranean summer conditions. Three commercial batches (A-C) were assessed using three stocking densities representing approximately the EFSA recommendation (LOW: 50-55 kg/m2), common commercial practice (MED: 66-71 kg/m2) and the upper commercial range (HIGH: 81-85 kg/m2), combined with two crate heights representing commercial practice (H20: 20 cm) and a height compatible with the EFSA recommendation (H40: 40 cm). Rabbits were monitored throughout pretransit (from catching and crating at the farm), transit (vehicle in route) and post-transit (unloading and lairage at the slaughterhouse) over 5.5-8.0 h, including 80-85 km of road transport. In-crate temperature, relative humidity, airflow, and vibration were monitored, while welfare was assessed using behavioural, thermophysiological and metabolic indicators. In-crate conditions were highly variable, with short thermal peaks of 30-33 °C during pretransit, relative humidity ranging from 30 to 85%, intermittent airflow peaking at 1.2-3.5 m/s and vibration levels of 1.24-1.53 m/s2 during transit. Immobility predominated (> 85% of observations) and exceeded 90% during transit, regardless of stocking density or crate height. Rabbits rarely sat upright with extended ears in H40 crates, particularly during transit (0.0-0.8%). No differences in thermophysiological or metabolic indicators were detected between stocking densities or crate heights. Overall, reducing stocking density from 81-85 to 50-55 kg/m2 and increasing crate height from 20 to 40 cm did not result in measurable welfare improvements under the commercial transport conditions evaluated.