Spontaneous intake of essential oils after a negative postnatal experience has long-term effects on blood transcriptome in chickens

The perinatal period is critical for farm animals which are very sensitive to external challenges at this stage; this is partly due to the immaturity of their digestive and immune systems and high demand on behavioural and physiological adaptation. In addition, recent studies have shown that perinatal stressors can be responsible for increased disease risk in adulthood. We therefore hypothesized that correct welfare-health (WH) management of the young animal would improve its ability to cope with various challenges encountered not only during early post natal life but also throughout its whole production life. This programme aims to mimick field issues in experimental designs to assess their short- and long-term effects on WH. For the chicken, the negative experience will be exposure to experimental conditions that reproduce the conditions encountered between hatching and delivery to the farm. For 24h after leaving the hatchery, the chicks will be kept without food and water in containers and subjected to a lower room temperature (22°C = cold vs 27°C = control) and shaking movements mimicking transport. Control animals will not be subjected to stressors after leaving the hatchery and will be placed in standard rearing conditions.