During transport from the farm to the slaughter house birds are often confined in crates with limited space. In this study we investigated how the confinement of male turkeys in crates of 40, 55 or 90 cm height for 6 h, affected the turkeys welfare. We used both behavioural observations and physiological measures and the study was carried out under experimental conditions. Thirty-six turkeys were placed singly in stationary crates for 6 h and during this time their behaviour was observed. The confinement for each bird was carried out twice on two separate occasions with around 1 week between confinements. The mean (±SE) weight of the birds in the first confinement period was 15.9 ± 0.2 kg and on the second occasion 17.3 ± 0.2 kg. Blood-samples were taken after the behaviour observations were finished and analyses of activities of creatine kinase (CK), aspartate aminotransferase (ASAT) and lactate were carried out. The heterophil:lymphocyte ratio (H:L) was also determined. The behaviour observations revealed that birds in the 40 cm crates did not perform any standing (standing with straight legs), whereas birds in 55 and 90 cm crates spent 35.4 ± 4.3 and 42.2 ± 5.8% of the time, respectively, in this position. Conversely, birds in the 40 cm crates spent significantly more time in a low standing position (standing with the legs bent) than birds in the 55 and 90 cm crates. More stepping, turning and preening was performed in the 55 and 90 cm compared to the 40 cm crates, whereas more rising attempts were made in the 40 cm crates. Crate height had no effect on the activity of ASAT or CK activity or H:L ratio. There was a significant effect of crate height on the lactate with birds in the 55 cm crates having significantly lower lactate concentrations than birds in 40 cm crates, but there was no significant difference in lactate concentration between 55 and 90 cm or between the 40 and 90 cm crates. This may indicate that there was a difference between treatments on the anaerobic activity, although the effect of sampling procedure cannot be completely excluded. Thus the degree of confinement in the crates had little influence on the physiological measures taken, although there was a large effect on the birds' behaviour. The 40 cm crates decreased the birds possibility to move and change their positions, whereas the 55 cm crates allowed the birds to stand up and move around almost as much as if kept in free height, even if they were not able to stretch their necks while standing.