Locomotor Behavior of Chickens Anticipating Incline Walking.

Chantal Leblanc,Alexandra Harlander-Matauschek,Bill Szkotnicki,Bret Tobalske

doi:10.3389/fvets.2017.00233

Chantal Leblanc, Alexandra Harlander-Matauschek + Show 2 more

Open Access

https://doi.org/10.3389/fvets.2017.00233

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Abstract

Keel bone damage (KBD) is prevalent in hens raised for egg production, and ramps between different tiers in aviaries have potential to reduce the frequency of falls resulting in KBD. Effective use of ramps requires modulation of locomotion in anticipation of the incline. Inadequate adaptive locomotion may be one explanation why domestic layer hens (Gallus gallus domesticus) exhibit high rates of KBD. To improve understanding of the capacity of hens to modulate their locomotion in anticipation of climbing, we measured the effects of incline angle upon the mechanics of the preparatory step before ascending a ramp. Because the energetic challenge of climbing increases with slope, we predicted that as angle of incline increased, birds during foot contact with the ground before starting to climb would increase their peak force and duration of contact and reduce variation in center of pressure (COP) under their foot. We tested 20 female domestic chickens on ramp inclines at slopes of +0°, +40°, and +70° when birds were 17, 21, 26, 31, and 36 weeks of age. There were significantly higher vertical peak ground reaction forces in preparation at the steepest slope, and ground contact time increased significantly with each increase in ramp angle. Effects upon variation in COP were not apparent; likewise, effects of limb length, age, body mass were not significant. Our results reveal that domestic chickens are capable of modulating their locomotion in response to incline angle.

Highlights

Keel bone damage (KBD) is a critical form of injury in commercial aviaries in which domestic chickens (Gallus gallus) are raised for egg production, but the sources of this injury are poorly understood [1]
We present data from one-foot force plate contacts, meaning our sample size for statistical analyses was limited to the same subset of birds that stepped with one foot on the platform regardless of incline
Our results provide novel insight into the capacity for adaptive locomotion in domestic chickens

Summary

Introduction

Keel bone damage (KBD) is a critical form of injury in commercial aviaries in which domestic chickens (Gallus gallus) are raised for egg production, but the sources of this injury are poorly understood [1]. Chickens routinely use various forms of locomotion in aviaries, including walking, running, climbing only using their legs and feet, using wing flapping to assist their hindlimbs during climbing, and flying using vigorous wing flapping [2]. The links between these forms of locomotion and the incidence of KBD are not well understood. Exciting new research has revealed that modifying aviary design to include ramps from the ground to elevated tiers and between tiers has the potential to reduce the frequency of falls or collisions and resulting KBD [3]. Recent work has demonstrated domestic chickens walk to climb 40° inclines and use wing-assisted incline running [WAIR; [8]] or aerial ascent when moving up steeper slopes [4]

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