# Prolonged production cycles in commercial laying hens and its bone repercussions

## TL;DR

This study shows that extended laying cycles in hens lead to poor bone health, with signs of osteoporosis and reduced bone density.

## Contribution

The study integrates QCT imaging with histopathology to reveal bone deterioration in aging laying hens under prolonged production cycles.

## Key findings

- Extended laying cycles and cage confinement cause significant bone quality decline in hens.
- Histopathology showed osteoporosis markers like increased cortical porosity and active osteoclasts.
- BMD varied significantly across tibial regions, with higher values in the medial region.

## Abstract

This study aimed to evaluate the impact of prolonged production cycles on bone quality in Dekalb White laying hens, focusing on bone mineral density (BMD), histopathological alterations, and serum biochemical parameters. A total of 10 Dekalb White hens at 83 weeks of age were assessed. Bone mineral density was evaluated using quantitative computed tomography (QCT). Histopathological analysis of the tibiae was performed, and serum biochemical markers related to bone metabolism were measured. The mean cortical tibial BMD was 847.19 ± 100.47 mg/cm³, with significant differences among tibial regions, as demonstrated by repeated measures ANOVA (P = 0.003 for the right tibia and P = 0.002 for the left tibia), with higher values observed in the medial region compared with the proximal region. Histopathology revealed signs of osteoporosis, including increased cortical porosity, trabecular bone resorption, Haversian canal enlargement, and a higher number of active osteoclasts. No significant correlations were observed between BMD values and serum biochemical parameters (Pearson’s and Spearman’s correlations; P > 0.05). These findings indicate that extended laying cycles combined with cage confinement negatively impact skeletal health in aging laying hens. The integration of advanced imaging techniques such as QCT with histopathological evaluation proved effective for detecting bone fragility and early skeletal deterioration.