Bone strength of caged layers as affected by dietary calcium and phosphorus concentrations, reconditioning, and ash content.

1. The effects of preconditioning, dietary calcium and phosphorus concentrations, ash content, body weight, and bone geometry on the shear strength of the radius of caged layers were investigated. 2. Birds that did not lay for three or more weeks before the end of the production period had higher radius bone strengths than the birds producing eggs. 3. Shear breaking force increased with bone ash content. 4. The shear breaking force and stress of the radius were not affected by increasing dietary calcium and phosphorus during the last 8 weeks of production. 5. Freezing and thawing before testing had no effect on bone strength. 6. Body weight cannot be used to predict the breaking force of the radius of caged layers.