Rearing experience with ramps improves specific learning and behaviour and welfare on a commercial laying farm

Kate I Norman,John F Tarlton,Christine J Nicol,Claire A Weeks

doi:10.1038/s41598-021-88347-9

Abstract

To access resources in commercial laying houses hens must move between levels with agility to avoid injury. This study considered whether providing ramps during rear improved the ability of birds to transition between levels. Twelve commercial flocks (2000 birds/flock) on a multi-age site were examined between 1 and 40 weeks of age. All birds had access to elevated perching structures from 4 days of age. Six treatment flocks were also provided with ramps during rear to facilitate access to these structures. Flocks were visited three times during rear and three times at lay to record transitioning behaviour and use of the elevated structures, together with scores for keel bone and feather damage. Ramp reared flocks used the elevated structures to a greater extent at rear (P = 0.001) and at lay, when all flocks had ramps, showed less hesitancy [i.e. pacing (P = 0.002), crouching (P = 0.001) and wing-flapping (P = 0.001)] in accessing levels. Mean levels of keel bone damage were reduced in ramp reared flocks (52%) compared with control flocks (64.8%) at 40 weeks of age (P = 0.028). The early life experience of the ramp reared flocks enabled specific learning that translated and persisted in later life and resulted in overall welfare benefits.

Highlights

To access resources in commercial laying houses hens must move between levels with agility to avoid injury
A greater mean (± SD) number of chicks were observed on the structures in the ramp reared (RR) groups (21.50 ± 17.44) compared to the control reared (CR) groups (13.99 ± 14.25) at all ages
There appear to be some differences between the rearing treatments at the three ages, an interaction effect was not found, which may be due to the sample size of 12

Summary

Introduction

To access resources in commercial laying houses hens must move between levels with agility to avoid injury. In free-range systems, access to the outdoor range can sometimes mean moving through elevated pop-holes Resources such as litter and the outside range are required for the performance of foraging[1] and dust bathing; which, together with night-time perching have been identified as behavioural needs[2]. Pettersson et al.[11] observed more behaviours indicative of hesitancy such as crouching, pacing and stepping on the spot when birds attempted to move between levels with no ramp provision compared to areas with ramps Alongside these benefits, the installation of ramps and platforms in commercial aviary systems has been found to reduce collisions by 59%, falls by 45% and keel bone fractures by 23% at 60 weeks of age[12].

Methods

Results

Conclusion