Early Onset of Laying and Bumblefoot Favor Keel Bone Fractures.

Sabine Gebhardt-Henrich,Ernst Fröhlich

doi:10.3390/ani5040406

Abstract

Simple SummaryNumerous studies have documented a high prevalence of keel bone fractures in laying hens. In this longitudinal study, 80 white and brown laying hens were regularly checked for keel bone deviations and fractures while egg production was individually monitored. About 62% of the hens had broken keel bones at depopulation. More new fractures occurred during the time when laying rates were highest. Hens with broken keel bones at depopulation had laid their first egg earlier than hens with intact keel bones. All birds with bumblefoot on both feet had a fracture at depopulation.Numerous studies have demonstrated influences of hybrid, feed, and housing on prevalence of keel bone fractures, but influences of behavior and production on an individual level are less known. In this longitudinal study, 80 white and brown laying hens were regularly checked for keel bone deviations and fractures while egg production was individually monitored using Radio Frequency Identification (RFID) from production until depopulation at 65 weeks of age. These focal birds were kept in eight pens with 20 hens per pen in total. About 62% of the hens had broken keel bones at depopulation. The occurrence of new fractures was temporally linked to egg laying: more new fractures occurred during the time when laying rates were highest. Hens with fractured keel bones at depopulation had laid their first egg earlier than hens with intact keel bones. However, the total number of eggs was neither correlated with the onset of egg laying nor with keel bone fractures. All birds with bumblefoot on both feet had a fracture at depopulation. Hens stayed in the nest for a longer time during egg laying during the ten days after the fracture than during the ten days before the fracture. In conclusion, a relationship between laying rates and keel bone fractures seems likely.

Highlights

Keel bone damage including deviations of the bone and fractures are common in laying hens, especially in non-cage housing systems, and present a major risk to the well-being of the animals [1,2,3,4]
In order to determine links between production and the presence of keel bone fractures, hens in this study were individually monitored throughout production for egg laying, occurrence of keel bone deviations and fractures, and behavior
The number of hens with keel bone deviations manifested a non-linear curve with increasing age

Summary

Introduction

Keel bone damage including deviations of the bone and fractures are common in laying hens, especially in non-cage housing systems, and present a major risk to the well-being of the animals [1,2,3,4].The presence of perchable objects (e.g., dedicated perches, as well as other items like water pipes) and their height are thought to be a primary factor in causing keel bone fractures due to collisions [5].Alternatively, fractures of the keel bone could be caused by the pressure perches exert on the perching bird [6,7,8]. The presence of perchable objects (e.g., dedicated perches, as well as other items like water pipes) and their height are thought to be a primary factor in causing keel bone fractures due to collisions [5]. Apart from perches and other housing equipment, de-mineralized bone, due to a high egg laying rate could influence the prevalence of keel bone fractures. Fleming et al [9] concluded that the most important factor influencing bone strength was genetics followed by the environment and nutrition. In order to determine links between production and the presence of keel bone fractures, hens in this study were individually monitored throughout production for egg laying, occurrence of keel bone deviations and fractures, and behavior

Results

Discussion

Conclusion