Modern laying hens have been selected for an astounding rate of egg production, but the physiological calcium demand takes a significant toll on their skeletal health. Bones can be assessed both in vivo and ex vivo, using a combination of different structural and mechanical analysis methods. Typically, the properties of leg, wing and keel bones are measured. Conventional caged layers are restricted in movement, which imbalances structural bone resorption and new bone formation, resulting in osteoporosis. Hens within alternative housing systems have opportunities to exercise for strengthening bones, but they can also suffer from higher rates of keel fractures and/or deviations that are likely to have resulted from collisions or pressure force. Limited research has been conducted within Australian commercial housing systems to assess hen skeletal health, including prevalence of keel damage across different system types. Research conducted on both brown and white hen strains approximately within the past decade internationally (2009 onward) has shown that skeletal health is impaired across all housing systems. Keel-bone damage is of specific concern as it occurs at high rates, particularly in multi-tiered systems, is painful, can alter hen behaviour, and reduce both production and egg quality. Management strategies such as the provision of ramps to access perches and tiers can reduce the incidence of keel-bone damage to a degree. Bone strength can be improved through exercise opportunities, particularly when available during pullet rearing. Genetic selection for high bone strength may be necessary for hens to adequately adapt to loose-housed systems, but the best strategy for improving skeletal health is likely to be multifactorial.

中文翻译：

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澳大利亚所有住房系统中层的骨骼健康和未来的研究方向

现代蛋鸡因其产蛋率惊人而被选中，但生理钙需求对其骨骼健康产生重大影响。使用不同结构和力学分析方法的组合，可以在体内和体外对骨骼进行评估。通常，测量腿骨、翼骨和龙骨的属性。传统笼养层的运动受限，导致结构性骨吸收和新骨形成失衡，导致骨质疏松症。替代鸡舍系统中的母鸡有机会锻炼以增强骨骼，但它们也可能遭受更高的龙骨骨折率和/或可能由碰撞或压力引起的偏差。在澳大利亚商业住房系统中进行了有限的研究来评估母鸡骨骼健康，包括不同系统类型龙骨损坏的普遍性。大约在过去十年间（2009 年以后）在国际范围内对棕色和白色母鸡品系进行的研究表明，所有鸡舍系统的骨骼健康都受到损害。龙骨损伤是一个特别值得关注的问题，因为它发生率很高，特别是在多层系统中，是痛苦的，会改变母鸡的行为，并降低产量和鸡蛋质量。管理策略，例如提供通往栖息地和层的坡道，可以在一定程度上减少龙骨损坏的发生率。可以通过锻炼机会提高骨骼强度，尤其是在后备母鸡饲养期间。