A Procedure Study of Bone Breakage in Spent Hens

PROCESSING of Leghorn type laying hens frequently results in the shattering of keel bones, rib cages and clavicles. Birds reared in cages present more of a problem than those reared on the floor. Bone breakage is greater with caged birds arriving at the processing plants and the bone breakage is further compounded by the de-feathering equipment. In extreme cases as many as 85 to 95 percent of the carcasses are not acceptable for deboning and further processing (Kralis, 1968). It has been shown that the laying hen will deplete its skeletal muscle of calcium when the calcium level of the diet is low (Common, 1938; Taylor and Moore, 1954). The percent of bone ash drops when pullets are fed a diet low in calcium (Taylor and Moore, 1954). Both bone ash and breaking strength appear to be related to bone strength (Rowland et al., 1967a, 1968a). Increasing the calcium level…