Keel bone fractures are associated with individual mobility of laying hens in an aviary system

Rufener, Christina; Abreu, Yudith; Asher, Lucy; Berezowski, John; Sousa, Filipe Maximiano; Stratmann, Ariane; Toscano, Michael J.

doi:10.1016/j.applanim.2019.05.007

Cited by 44 publications

(51 citation statements)

References 41 publications

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“…The differing phenotype of the white LSL hens facilitated the identification and catching of focal LB hens throughout the study. Three other pens in the barn contained focal LSL hens with a majority of LB hens, but as this strain was not sampled for quantification of AHN, their results are not reported here (see Rufener et al 16 for mobility data). In addition to spiral leg rings colour-coded for pen (Fieger AG, Untertuttwil, Switzerland), focal hens were marked with flexible legbands (Roxan Developments Ltd, Selkirk, United Kingdom) displaying individual identification numbers.…”

Section: Animals and Housing One Day Old Lohmann Brown (Lb) And Lohmanmentioning

confidence: 95%

“…arrived at the Aviforum research facility in Zollikofen, Switzerland, where they were housed within eight mixed hybrid rearing pens. The study reported here was part of a larger effort, the facilities and management protocols of which are described in full by Rufener et al 16 . At 18 weeks of age, hens were transferred to a commercial aviary system for laying hens within a layer barn on site.…”

Section: Animals and Housing One Day Old Lohmann Brown (Lb) And Lohmanmentioning

confidence: 99%

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Keel bone fractures induce a depressive-like state in laying hens

Armstrong

Rufener

Toscano

et al. 2020

Sci Rep

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In commercial flocks of laying hens, keel bone fractures (KBFs) are prevalent and associated with behavioural indicators of pain. However, whether their impact is severe enough to induce a depressive-like state of chronic stress is unknown. As chronic stress downregulates adult hippocampal neurogenesis (AHN) in mammals and birds, we employ this measure as a neural biomarker of subjective welfare state. Radiographs obtained longitudinally from Lohmann Brown laying hens housed in a commercial multi-tier aviary were used to score the severity of naturally-occurring KBfs between the ages of 21-62 weeks. Individual birds' transitions between aviary zones were also recorded. Focal hens with severe KBFs at 3-4 weeks prior to sampling (n = 15) had lower densities of immature doublecortinpositive (DCX +) multipolar and bipolar neurons in the hippocampal formation than focal hens with minimal fractures (n = 9). KBF severity scores at this time also negatively predicted DCX + cell numbers on an individual level, while hens that acquired fractures earlier in their lives had fewer DCX + neurons in the caudal hippocampal formation. Activity levels 3-4 weeks prior to sampling were not associated with AHN. KBFs thus lead to a negative affective state lasting at least 3-4 weeks, and management steps to reduce their occurrence are likely to have significant welfare benefits. Keel bone fractures (KBFs) present a serious welfare problem for the egg production industry, given that between 20 to 96% of birds within commercial flocks in various countries are reported to have some level of damage (Belgium 1 ; Canada 2 ; Denmark 3 ; The Netherlands 4 ; Switzerland 5,6 ; and the UK 7-9). Estimates of KBF prevalence increase with age, rising from 5.5% of birds affected within a flock at onset of lay 10 to as many as 97% by the end of a production cycle 4. Many KBFs appear to arise from collisions, both with perches 11 , which hens are highly motivated to use 12 , and other equipment including drinkers and support beams. Although the presence of a KBF does not suppress perching behaviour 13 , it does reduce frequency of range access via popholes 14. Further behavioural evidence also supports the assumption that KBFs are a source of pain or discomfort for laying hens (reviewed by Riber et al. 15), with recent studies demonstrating their association with altered movement throughout the aviary 16,17. Focusing on more direct assessments of movement and pain, hens with KBFs display greater latencies to fly down from perches 100 and 150 cm above the floor to obtain a food reward than hens without fractures, whilst delays in fractured birds alone are reduced following administration of various analgesics 18-20. Furthermore, a conditioned place preference for the location in which the analgesic was administered is observed to develop only in hens with KBFs 21. While this indicates that short-term relief from pain arising from keel fractures is a reinforcing occurrence, whether their un-medicated experience is negative and/or salient enough to produ...

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Section: Animals and Housing One Day Old Lohmann Brown (Lb) And Lohmanmentioning

confidence: 95%

Section: Animals and Housing One Day Old Lohmann Brown (Lb) And Lohmanmentioning

confidence: 99%

Keel bone fractures induce a depressive-like state in laying hens

Armstrong

Rufener

Toscano

et al. 2020

Sci Rep

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“…Another hypothesis to explain the higher incidence of KBF at the age of 31-33 weeks would be that, after moving the hens from the rearing to the laying barn, hens need to adapt to their new environment and might use the lower perches of the aviary less than the upper perches. Indeed, use of the upper perches increases with increasing age (13) and was found to be a risk factor for KBF (20). After a linear increase in KBF incidence leading to a peak at P4, this will reduce again due to a lower use of the perches.…”

Section: Fracture Developmentmentioning

confidence: 99%

“…eu/activities/practical-information-for-stakeholders/onlinetool-for-evaluating-fractures-from-radiographic-images/>) that was determined to be reliable in terms of intra-and interobserver reliability (12). The protocol was successfully used to grade fractures in relation to hen productivity (12) and mobility (13). Although Rufener et al (12) included presence of a fracture gap to indicate healing, the protocol was fairly narrow in scope.…”

Section: Introductionmentioning

confidence: 99%

Radiographic Evaluation of Keel Bone Damage in Laying Hens—Morphologic and Temporal Observations in a Longitudinal Study

et al. 2020

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The keel bone of commercially kept laying hens is known to be frequently affected by morphologic changes such as fractures and deformations with important implications for animal welfare. To detect morphologic changes, various methods such as palpation, computed tomography, and ultrasound are available, though radiography allows for the greatest level of detail in combination with the most ease of use. To explore the benefits of radiography in providing objective data on keel fractures from the age of 22-61 weeks within a single laying period, the keel bones of 75 Lohmann Brown and 75 Lohmann Selected Leghorns were radiographed every 3 to 5 weeks. Type, location, angulation, dislocation, callus formation, and healing process were assessed descriptively for each lesion. Ninety-nine percent of the animals showed at least one keel bone lesion during the study and 97% of the animals had at least one keel bone fracture. In 77% of the cases, the caudal third of the keel bone was affected. The fracture types were transverse and oblique (88%), comminuted, and butterfly. Further lesions were sclerosis, new bone formation and angulation. For each keel bone, an average of three fractures (3.09 ± 1.80) was detected at the end of the study. The described radiographic protocol for keel bone lesions was suitable for longitudinal, on-site examinations in conscious laying hens. Our results also indicate that keel bone fractures are more frequent than reported in earlier studies. The described radiographic examination protocol can be used to perform comparative studies of palpatory findings, or to assess the clinical significance of different fracture types which require a high level of detail.

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“…The possible impact of keel bone fractures, in particular, on production and welfare parameters have received quite a lot of attention by different research groups. In general, keel bone fractures are considered to be painful and reduce mobility [15][16][17][18][19]. The impact on production parameters appear to be less documented, however, increased feed conversion and reduced laying and egg quality have been reported [15][16][17][18]20].…”

Section: Introductionmentioning

confidence: 99%

Pathological characterization of keel bone fractures in laying hens does not support external trauma as the underlying cause

et al. 2020

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Keel bone fractures in laying hens have been described with increasing prevalence from several countries over the last twenty years and are considered one of the greatest welfare problems to the layer industry. In Denmark we have observed fracture prevalence in the range of 53% to 100% in flocks from cage-free systems whereas flock prevalences in birds from enriched cages ranged between 50-98%.Previous research have speculated that the underlying reason for the development of keel bone fractures is trauma in relation to impact of the bird with furniture, other equipment etc. However, little evidence of this theory has been provided. Predisposing factors have also been suggested including genetics of the bird, lack of specific feedstuff components, high egg production, management factors and layer fatigue.This study has addressed the possible pathogenesis of these fractures by pathological characterization of fractures in birds from different production systems. More than 60 keel bones with fractures have been characterized histo-pathologically and by CT scan. This included an assessment of damage to muscles and soft tissues, the bone and the healing process including callus formation. This investigation has shown that high energy collisions cannot be responsible for the majority of fractures, located at the caudal tip of the keel bone, observed in laying birds as markers associated trauma were not observed in the majority of the cases just as few recognized healing processes were observed. These results suggest an alternative pathogenesis to trauma. OPEN ACCESS Citation: Thøfner I, Hougen HP, Villa C, Lynnerup N, Christensen JP (2020) Pathological characterization of keel bone fractures in laying hens does not support external trauma as the underlying cause. PLoS ONE 15(3): e0229735.

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Keel bone fractures are associated with individual mobility of laying hens in an aviary system

Cited by 44 publications

References 41 publications

Keel bone fractures induce a depressive-like state in laying hens

Keel bone fractures induce a depressive-like state in laying hens

Radiographic Evaluation of Keel Bone Damage in Laying Hens—Morphologic and Temporal Observations in a Longitudinal Study

Pathological characterization of keel bone fractures in laying hens does not support external trauma as the underlying cause

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