The effect of laying hen strain on perching biomechanics and keel deviations
Bibliographic record
Abstract
Keel bone damage ( KBD ), including deviations and fractures, is a welfare concern in laying hens leading to pain and decreased egg production. Shifting towards alternative housing systems has highlighted a need to evaluate how laying hen strain and perch shape contributes to perching biomechanics and KBD. Our study aimed to determine the effect of strain on perching biomechanics, keel deviations, body weight, and bone composition. Four commercial strains (Lohmann White, Shaver White, Lohmann Brown, ISA Brown) and two random-bred strains (Shaver Rhode Island Red and Antique White Leghorn) were studied ( n = 20/treatment). Perching kinematics were evaluated on round and mushroom-shaped perches at 18, 29, and 70 weeks of age using continuous kinematic recordings. Instability indicators while perching included movement speed and motion in the x- (side-side), y- (forward-backward), and z-axes (up-down). Dual x-ray absorptiometry was used to assess bone parameters (femur and keel bone mineral content and density). Keel deviation severity was assessed via digital imaging post-mortem. Rhode Island Red hens had greater femur bone mineral density and content compared with all other strains evaluated. Higher-producing commercial strains had more incidences of severe keel deviations. Round perches led to faster forward-backward and up-down movements compared to mushroom perches. Commercial strains moved up-down more and forward-backward less than random-bred strains. Up-down movements were correlated with higher incidences of severe keel deviations. Overall, both strain and perch shape effected perching biomechanics. Specifically, round perches contributed to instability while perching. Commercial strains with more severe keel deviations moved up-down more than random-bred strains.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".