Transport of 18-day old hatching eggs - effects on physiology and behaviour in broiler chicken?

Incubation, hatching, and raising of broiler chicken commonly takes places at separate facilities. Recently, hatching at the grow-out facility is tested, avoiding the transport of day-old chicks. Instead, eggs are transported on embryonic day 18 from the breeding to the grow-out facility, where they hatch on day 21. Transport is a known stressor to animals. As the Hypothalamic–pituitary–adrenal (HPA)-axis becomes functional around embryonic day 14-16, it is conceivable that transport of eggs may lead to a stress response and increased production of corticosterone in the embryo. Exposure to prenatal stress may program the HPA axis in the long term, affecting the coping capacity of the individual and negatively impacting the further development of the chick. Moreover, malpositioning (the embryo turning towards the “wrong” end of the egg) of late-stage embryo seems to occur more often after transport of long durations, leading to hatching failure. In this project we will investigate whether prolonged transport on day 18 has effects on the development of a slow growing broiler chicken strain. We measure the heart rate of embryos during transport and later hatching success of the chicks. We perform several established behavioural tests related to stress susceptibility, such as tonic immobility (TI) and open field (OF). Moreover we determine corticosterone concentrations in feathers at the end of the experiment. We expect chicks that underwent longer prenatal transport to show stronger behavioural responses to stressful challenges, e.g., show a longer duration of TI, and higher levels of feather corticosterone compared to chicks that experienced short transport.