Some hens move more often between the different levels in their coop, depending on their personality. | Image: Sabine Gebhardt

Some animals are spirited and eager to get about, while others are more cautious and inactive. A research team at the University of Bern, led by Michael Toscano, has now shown that such personality traits in hens remain stable over the long term. They attached lightweight location trackers to 194 laying hens, and investigated five specific behavioural traits among the animals over the course of eight months. These were: “sleeping, feeding, nesting, indoor movements and outdoor usage”. In all these instances, they found differences among the animals that were dependent on their respective personality. “Some laying hens move much more often than others between the different levels in their coop”, says Toscano.

This individuality of behaviour was maintained, even when conditions changed suddenly – such as an onset of cold temperatures, or immediately after the hens were vaccinated. Toscano explains that long-term studies like this are enormously important because an aspect of behaviour can only be deemed a personality trait if it remains stable over time. “A spirited hen will always be more spirited than a shy one”.

Some personality traits are closely related to each other. Hens that moved around a lot in the coop also used their outside enclosure more often, and reacted more quickly when fresh food was provided. Toscano says that these combined traits offer an important guide towards breeding more robust laying hens. If you know which traits are linked and how they relate to the hens’ well-being, you can use that knowledge when selecting animals for breeding purposes. This is precisely what the researchers from Bern are currently doing in a large-scale project.

C. M. Montalcini et al.: Commercial laying hens exhibit long-term consistent individual differences and behavioural syndromes in spatial traits. R. Soc. O. Sci. (2023)