Keel bone damage and associated physiological parameters in traditional chicken breeds and hybrid layers
7 affiliations
- 1Institute of Animal Welfare and Animal Husbandry, Friedrich-Loeffler-Institut , ,
- 2Institute for Animal Science – Farm Animal Ethology, University of Bonn , ,
- 3Poultry Research Center, Bruno-Dürigen Institute , ,
- 4Medical Faculty and University Hospital Düsseldorf, Institute for Anatomy I, Heinrich Heine University Düsseldorf , ,
- 5Chair of Animal Welfare, Ethology, Animal Hygiene and Animal Husbandry, Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-University , ,
- 6Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut , ,
- 7Institute of Animal Hygiene and Veterinary Public Health, Faculty of Veterinary Medicine, Leipzig University , ,
Abstract
Introduction: Keel bone damage is an important welfare issue in laying hens. Although some risk factors have been identified, the etiology is not fully clear. In previous studies, traditional breeds exhibited less keel bone fractures than hybrid layers.
Aim: Thus, this study aimed at finding out more about potential influencing factors by comparing two traditional breeds, Rhode Island Red (RHO) and American Leghorn (AL), and the two different hybrid layers Lohmann Brown Classic (LB) and Lohmann Sandy (LSA) in terms of keel bone damage and potentially related parameters.
Methods: The animals were kept in groups of 12 hens and one or two roosters, under natural daylight conditions, and with access to outdoor enclosures. Blood sampling was conducted at five and radiography at six time points between the 16th and 72nd week of age. The radiographs of the keel bones were evaluated for keel bone fractures, deviations, radiographic density, ossification, and length. Furthermore, the concentration of blood ionized calcium and plasma total calcium, phosphate, 17β-estradiol, and follicle-stimulating hormone (FSH) was measured.
Results: The overall prevalence of keel bone fractures was significantly higher in LB and LSA (90.1% and 87.5%, respectively) compared to RHO (0%) and AL (9.1%). RHO were larger and started laying distinctly later than the other genotypes. In addition, prolonged weight gain and less progressed keel bone ossification in the 24th week of age compared to the other genotypes indicate slower physical development. The results on radiographic density, ossification, and age at first egg indicate that ossification and possibly mineralization were less progressed in the hybrid layers than in AL at onset of lay. Plasma 17β-estradiol increased around the onset of lay, but did not significantly differ between the genotypes during the laying period. Furthermore, between the 33rd and 52nd week of age, there was a significant increase in plasma FSH in all genotypes, which may be attributable to seasonal changes in the length of daylight.
Discussion/Conclusion: In summary, this study offers insights into keel bone health, bone traits, and reproductive parameters in different chicken genotypes, which may improve understanding and contribute to future strategies to reduce keel bone damage.
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BibTeX
@article{hildebrand2026keel,
title = {{Keel bone damage and associated physiological parameters in traditional chicken breeds and hybrid layers}},
author = {Lisa Hildebrand and Saskia Neukirchen and Mareike Fellmin and Julia Mehlhorn and Stefanie Petow and Lars Schrader and Jenny Stracke and Steffen Weigend and Beryl Eusemann-Keller},
journal = {Frontiers in physiology},
year = {2026},
month = oct,
doi = {10.3389/fphys.2026.1973493},
url = {https://europepmc.org/article/PMC/PMC13727405},
note = {CC BY},
}
RIS
TY - JOUR
TI - Keel bone damage and associated physiological parameters in traditional chicken breeds and hybrid layers
AU - Lisa Hildebrand
AU - Saskia Neukirchen
AU - Mareike Fellmin
AU - Julia Mehlhorn
AU - Stefanie Petow
AU - Lars Schrader
AU - Jenny Stracke
AU - Steffen Weigend
AU - Beryl Eusemann-Keller
PY - 2026
DA - 2026/10/20
JO - Frontiers in physiology
DO - 10.3389/fphys.2026.1973493
UR - https://europepmc.org/article/PMC/PMC13727405
AB - Introduction: Keel bone damage is an important welfare issue in laying hens. Although some risk factors have been identified, the etiology is not fully clear. In previous studies, traditional breeds exhibited less keel bone fractures than hybrid layers. Aim: Thus, this study aimed at finding out more about potential influencing factors by comparing two traditional breeds, Rhode Island Red (RHO) and American Leghorn (AL), and the two different hybrid layers Lohmann Brown Classic (LB) and Lohmann Sandy (LSA) in terms of keel bone damage and potentially related parameters. Methods: The animals were kept in groups of 12 hens and one or two roosters, under natural daylight conditions, and with access to outdoor enclosures. Blood sampling was conducted at five and radiography at six time points between the 16th and 72nd week of age. The radiographs of the keel bones were evaluated for keel bone fractures, deviations, radiographic density, ossification, and length. Furthermore, the concentration of blood ionized calcium and plasma total calcium, phosphate, 17β-estradiol, and follicle-stimulating hormone (FSH) was measured. Results: The overall prevalence of keel bone fractures was significantly higher in LB and LSA (90.1% and 87.5%, respectively) compared to RHO (0%) and AL (9.1%). RHO were larger and started laying distinctly later than the other genotypes. In addition, prolonged weight gain and less progressed keel bone ossification in the 24th week of age compared to the other genotypes indicate slower physical development. The results on radiographic density, ossification, and age at first egg indicate that ossification and possibly mineralization were less progressed in the hybrid layers than in AL at onset of lay. Plasma 17β-estradiol increased around the onset of lay, but did not significantly differ between the genotypes during the laying period. Furthermore, between the 33rd and 52nd week of age, there was a significant increase in plasma FSH in all genotypes, which may be attributable to seasonal changes in the length of daylight. Discussion/Conclusion: In summary, this study offers insights into keel bone health, bone traits, and reproductive parameters in different chicken genotypes, which may improve understanding and contribute to future strategies to reduce keel bone damage.
SN - 1664-042X
ER -