Light exposure during incubation and social and vigilance behaviour of domestic chicks
Anette Wichman1, Rafael Freire, Lesley J Rogers
1Swedish University of Agricultural Sciences, Skara, Sweden. Anette.Wichman@hmh.slu.se
Insights
Light exposure during incubation influences chick behavior. Chicks exposed to light showed altered social competition and predator vigilance compared to those incubated in darkness.
Area of Science:
- Animal Behavior
- Developmental Biology
- Neuroscience
Background:
- Prenatal light exposure can influence postnatal development.
- Lateralized visual behavior in chicks is known to be affected by light exposure during incubation.
Purpose of the Study:
- To investigate the impact of prenatal light exposure on post-hatching social behavior and vigilance in chicks.
- To determine if light exposure during a sensitive incubation period affects social competition and predator response.
Main Methods:
- Groups of chicks were incubated either in darkness (Da), light (Li), or a mix (Mixed).
- Chicks were tested on social competition tasks (access to food) and vigilance for a simulated predator.
- Behavioral responses, including looking up and food bowl access, were recorded.
Main Results:
- Lowest-ranking chicks in light-exposed groups had reduced access to food compared to dark-incubated chicks.
- Mixed groups exhibited social competition similar to light-exposed groups.
- Dark-incubated chicks showed different vigilance patterns, with fewer looking up before a predator stimulus but more looking up during its presentation.
Conclusions:
- Prenatal light exposure significantly influences post-hatching social dynamics and vigilance behaviors in chicks.
- The effects of light exposure are evident in both social competition and predator detection.
- These findings highlight the critical role of sensory experience during incubation on subsequent behavioral development.
Abstract:
Light exposure of chick eggs during a sensitive period at the end of the incubation period leads to the development of lateralised visual behaviour, and here we show that social behaviour is also influenced by this exposure. Groups of eight chicks of three types-(1) all incubated in the dark (Da), (2) all exposed to light (Li), (3) half Da and half Li (Mixed)-were tested on a range of tasks involving social competition and vigilance for a simulated predator. We confirmed a previous finding that lowest-ranking chicks in Li groups gained less access to a food bowl when they had to compete with group members than did the lowest-ranking chicks in the Da groups, and we extended this result to show that the Mixed groups performed like the Li groups. We also showed that before presentation of a novel stimulus resembling a predator, fewer of the chicks in the Da groups than in the Li and Mixed groups looked up, but during presentation of the predator more Da than Li chicks looked up. Hence, light exposure before hatching affects post-hatching social and vigilance behaviour.
