Environmental change or choice during early rearing improves behavioural adaptability in laying hen chicks

Abstract

Laying hens are typically moved to a novel environment after rearing, requiring adaptability to cope with change. We hypothesized that the standard rearing of laying hen chicks, in non-changing environments with limited choices (a single variant of each resource), impairs their ability to learn new routines, use new equipment and exploit new resources. On the contrary, rearing in a changing environment that also offers a choice of resource variants could better prepare chicks for the unexpected. To explore this hypothesis, environmental change and choice were manipulated in a 2 × 2 factorial experiment. Compared to standard rearing, greater change during early rearing, through repeatedly swapping litter and perch types, reduced initial freezing when exposed to a novel environment suggesting a lower fear response. Greater choice during rearing, through simultaneous access to multiple litter and perch types, resulted in shorter latencies to solve a detour task, more movement in novel environments and less spatial clustering, suggesting improved spatial skills and higher exploration. However, combining both change and choice did not generally result in greater improvement relative to providing one or the other alone. We conclude that environmental change and choice during rearing have different positive but non-synergistic effects on later adaptability potential.

Dynamics of changes in broiler spatial distribution induced by a robot with autonomous navigation along the growing cycle

“…Additionally, during the first 3 wk of age, when broilers are more active, few birds were also observed seeking physical interactions with the robot by approaching and even pecking at it. Thus, behavioral findings further support a habituation process where novelty is reduced via regular exposure to the same objects ( Jones and Waddington, 1992 ; Jones, 1996 ) especially since it was provided at early ages ( Skånberg et al, 2023 ). In fact, from the 2nd wk onward, there were no significant increases in bird density before the robot´s entrance, suggesting that the robot's movement induces a slightly “pushing” or gentle “get out of the way” effect rather than a response driven by fear-induced avoidance.…”

Commercial hatchery practices have long-lasting effects on laying hens’ spatial behaviour and health

“…In addition to the potential effect of early-life stressors, it is possible that the STAN chicks may have exhibited faster acclimatization to their new environment due to the inherent effects of their transition from the hatchery to the farm. As suggested by Skånberg et al [ 62 ], it is possible that environmental change during rearing plays a role in enhancing layer chicks’ adaptability later in life. Specifically, STAN hens may have learned appropriate cognitive and locomotive skills during the rearing period, facilitating their adaptation to the aviary system.…”

The necessity of pen replication to account for and understand the impacts of social dynamics on individual laying hen behavior

“…Temperament traits and cognitive processes are manipulable. They can vary depending on the history of the individual hen, such as the complexity of the developmental environment they were exposed to, early stressful experiences, access to specific environmental resources, and lighting conditions (Sobotik et al, 2020;Hedlund et al, 2021;Dumontier et al, 2023;Skånberg et al, 2023). Behavioral tests of temperament and cognition can be valid measures of the impacts of housing and management variation on these individual laying hen traits.…”