Of nature and nurture: the role of genetics and environment in behavioural development of laying hens

- Behavioural development is decided by the interplay between genetics and environment.
- Epigenetic and hormonal effects are closely related and can result in fast adaptation.
- Early-life conditions have strong effects on behavioural development which can result in adaptive changes.
- Effects of manipulations during early life should be investigated across multiple generations.

Behavioural development of birds is shaped by the complex interplay between genetics and environment. It is becoming increasingly clear that experiences of previous generations are transferred to the offspring through epigenetic and hormonal effects and result in lasting changes in behaviour. After hatching, social and physical conditions during early life have marked effects on bird behaviour of both the current and following generations. Aspects like the presence or absence of maternal care, the composition of the social environment and the behavioural stimulation offered by the physical environment all have strong influences on the behavioural development of a bird. Research approaches that focus on manipulations during the early-life period and investigate effects on epigenetics, maternal hormones and behavioural development should be encouraged.