Tonic immobility tests were conducted at day 5 and week 6, 26 control and 27 hatchery chickens were used at day 5 and 25 control and 24 hatchery chickens were tested at week 6. All chickens were selected randomly from their home pen and carried into the test room. One experimenter was responsible for inducing all tonic immobility and the second experimenter was responsible for timing the experiment. Once in the test room the chicken was placed on its back on a cradle, light pressure was applied to the body with 2 hands for 10 seconds to induce tonic immobility. If the chicken righted itself within 5 seconds it was deemed tonic immobility was not established, and the process was repeated for up to another two times. The time of first vocalisation, first head movement and rightening was recorded as well as the frequency of vocalisations whilst in tonic immobility. Tests were recorded in case there was any uncertainty in timing so it could be reviewed, if needed, at a later date.