Effect of simulated long transport on behavioural characteristics in two strains of laying hen chicks

Newly hatched chicks are routinely subjected to varying durations of transport shortly after hatching. Because little is known about the effects of this putative stressor on behavioural development, the present experiment tested for the effects of a simulated long transport-like treatment during the first day of life in two strains of laying hen chicks on growth, the development of perching behaviour, fear of humans (measured as the duration of tonic immobility induced by manual restraint) and the willingness to compete for access to feed. Fourty newly hatched Hy-Line W-36 (W-36) and 40 Hy-Line Brown (HB) chicks distributed over two blocks were subjected either to a short duration of handling and transport prior to delivery at the laboratory (SHORT treatment; duration of 4h) or to the same treatment plus an additional period of intermittent movement used to simulate longer transport (LONG treatment; duration of 14h). LONG birds started perching at a significantly earlier age than SHORT birds (P <0.01), but strain effects on the duration or frequency of perching were non-existent or sporadic. W-36 birds had a longer duration of tonic immobility than HB birds (P <0.001) but there was no effect of the treatment (P >0.10). The treatment reduced the birds' willingness to compete for feed (P <0.02), but this was mainly due to an effect on W-36 birds, as indicated by an interaction between treatment and bird strain (P <0.02). The results thus indicate that the LONG treatment reduced the age at which birds first used perches and reduced the willingness to compete for feed. However, as these results were rather sporadic we could not show that the long transport-like treatment of day old chicks has wide-reaching effects on behavioural development. Further studies are needed to assess the long-term effect of transport duration on chicks and laying hens.