Quality assessment of spent laying hens and analysis of influencing factors.

In China, a considerable number of spent laying hens are disposed annually, with the majority being processed into various food products. The sale of spent laying hens has become a significant revenue stream within the poultry industry. We selected spent laying hens at 100 weeks of age as the research subjects to explore the factors influencing their market price. Information was gathered through product and enterprise investigations. Thereafter, 90 Rhode Island Red laying hens, also at 100 weeks old, were acquired for slaughter. The carcass evaluation was conducted utilizing the methodology prescribed by the United States Department of Agriculture (USDA). Tibial specimens were procured for the purpose of quantifying their length, mass, diameter, maximum breaking strength, maximum breaking distance, as well as for determining the concentrations of calcium, phosphorus, and ash content. Through comprehensive market research and industry surveys, this study found that the primary factor affecting the selling price of spent laying hens is body weight, with 1.5 to 2 kg of chickens being preferred. The USDA quality assessment standards for post-slaughter evaluation, it was found that the incidence of dislocation was 11.1 %, which emerged as a primary factor affecting carcass quality, directly resulting in a decline in quality. The results of the correlation analysis showed that there was no significant relationship between the bone health status and dislocation in laying hens. Dislocations occur mainly due to direct external forces during the culling process caused by the injuries during the slaughter process. Surveys show that the main factor affecting the selling price of spent laying hens is body weight, and the optimal weight range is where farmers gain price advantages during the culling process. The principal factor impacting the carcass quality of spent laying hens is dislocation, which are mainly caused by excessive culling and have no obvious correlation with bone health.