Feed withdrawal and Leghorn hen carcass composition

Abstract

Rendering is an important alternative to food processing for the disposition of spent commercial laying hens in areas where fowl processors are distant farms or when prices for spent hens are very low. Fasting commercial laying hens at the end of production allows egg producers to increase income from egg sales by not having to pay feed costs for a few days. This extra income can help offset the costs of flock removal. However, if fasting alters body composition, it could affect the value of spent hens to a renderer. This, in turn, would affect the length of fast that would maximize net returns. To investigate the possibility that fasting changes hen carcass composition, second-cycle hens in two commercial flocks were fasted for periods of 0 to 3 days and then killed. The feather-picked carcasses were analyzed for water, protein, fat, ash, calcium, phosphorus, and a variety of trace elements. Although there were significant differences between the two flocks in water, fat, ash, and phosphorus content, the length of time off feed appeared to have little influence on carcass composition. This suggests that the value of spent hens based on body composition does not change on a per pound basis during a fast. Egg producers, therefore, can fast hens to maximize net return from egg sales without having to account for more than the simple daily loss of body weight.