Posted by Akukwu Chioma

Protecting Laying Hens from Keel Bone Fracture



Keel Bone Fractures in Laying Hens: A Systematic Review of Prevalence across Age, Housing Systems, and Strains



 In modern egg production, laying hens (Gallus gallus domesticus) face a number of clinically evident welfare problems, of which keel bone damage is among the most prevalent. The challenge of accurately describing the extent of KBF prevalence has reflected on the multifactorial nature of the problem. 




The implementation of non-cage housing systems allows for hens to participate in more natural behaviors that are limited in a conventional caging system One consequence is a greater risk for keel bone damage to occur as well as a possibility of the hen to feel pain associated with that Keel bone damage and the possibility of pain can lead to a decreased welfare quality status of the hen and may impact other areas such as production. 

Growing Interest in Keel Bone Damage

It is widely recognized that today’s laying hen has poor skeletal health. Specifically, damage and fracture of the keel bone (the prominent ridge on the sternum of flighted birds to which the powerful wing muscles attach) is increasingly considered to be one of the most significant welfare problems within the egg industry.
Therefore, there has been a significant growing interest in research due to its impact in the industry and this has often coincided with regulatory and scientific milestones which sparked discussions about improving poultry welfare.



Figure 1. The number of studies assessing KBF (total of 88 studies) published over the last 30 years (1989 to 2018). Scientific and regulatory milestones discussing the improvement of poultry welfare are indicated with arrows


CAUSES OF KEEL BONE FRACTURE

The high frequency of damage seen in the keel bone (a bone extending from the sternum) of laying hens within commercial systems represents one of the greatest welfare problems facing the industry.
  • The prevalence of keel bone fractures extends to almost all the housing system(including traditional battery cages, furnished cages and non-cage systems)
  • Genetic lines
  • Management styles
  • Nutrition
  • Perch designs and height
  • Bird age and strain
  • Laying and rearing environments
Images on different research study on the impact of keel bone fracture






                                                                                    
        
                                                             
        



                


                           


Impact of Perch 

 The presence of perches has been associated with higher incidence of damage in the keel bone. High-impact injuries, unequal wing-loading during wing-flapping, perch use and compression fractures due to osteoporosis are the main causes of keel bone damage which can take different forms, including fractures, deformations, or indentations along the ventral edge of the bone. Although soft perches increases the spread of pressure on the keel bone deviations, however, in some countries, slatted floors and ramps are currently used as perches to reduce the pressure on the keel bone. Therefore perch materials and designs are important factor to consider when designing the housing.


                                                                                           

                                 



Solution Recommendation

  1. A uniform method of evaluating KBD should be employed with relevant criteria to ensure reliability of results
  2. Investigate low energy, non-collision events as a source of KF
  3. Investigate the role of bird development in KBD susceptibility
  4. Investigate the role of escape reactions as a source of KF
  5. Investigate genetic capacity to reduce KBD
  6. Investigate housing adaptations that affect frequency of KBD
  7. Investigate nutritional solutions to reduce KBD
Abbreviations
  • KBF-  keel bone fractures
  • KBD- keel bone damage
  • KF-    keel fracture

Resource and image References 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7597989/ https://www.frontiersin.org/articles/10.3389/fvets.2018.00006/full 
Type/tecno-poultry-systems/rearing-systems/aviary-rearing/ideal-fas https://www.sciencedirect.com/science/article/pii/S0032579119305772 
https://lohmann-breeders.com/breeding-for-better-bones-genetic-influence-on-the-reduction-of-bone-fractures-in-layers/ 
https://www.researchgate.net/figure/Scale-used-to-measure-the-severity-of-damage-to-the-keel-bone-left-to-right-score_fig8_221754311
https://www.poultryequipment.com/en/resources/projects/aviary-open-system-for-free-range-layers-the-pinilla-case-in-spain.html?tags=agco:product
https://midwestpoultry.com/wp-content/uploads/Purdum-Sheila-Strategies-to-Improve-Keel-Bone-Strength-and-Skeletal-Integrity-of-Laying-Hens-in-Various-Housing-Systems.pdf













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