Phosphorus in the Nutrition of the Adult Hen

DURING a series of experiments conducted in this laboratory between 1961 and 1967 on the relative availability of phosphorus from various sources for caged hens, unexpected mortality was observed to which osteoporosis appeared to be a major contributing factor. The syndrome resembled “cage layer fatigue” (CLF) as first described by Couch (1955) and later in greater detail by Grumbles (1959). A similar condition has since been reported elsewhere in the world by Bell and Siller (1962, Scotland), Gardiner (1964, Ireland), Smetana (1965, Australia), and Hartwigk (1966, Germany). Genetic differences in susceptibility were reported by Francis (1957) based on variations in incidence of CLF from 0.65% to 3.95% in seven strains of birds. Several reports have implicated skeletal weakness or damage in the condition. Urist and Deutsch (1960) described severe osteoporosis in White Leghorn hens in heavy egg production and noted that it did not occur in immature and young mature…