Density and breaking strength of bones of mortalities among caged layers.

The incidence of deaths attributable to cage layer osteoporosis (CLO) and the associated parameters of bone strength were studied in a flock of 5000 commercial laying hens over one laying cycle. Of the 9.7 per cent mortality rate, 35 per cent were attributed to CLO, and the mean age of death of the CLO hens (45.5 weeks) was significantly earlier than that of the non-CLO hens (51.6 weeks). There was a significant linear relationship between the density and breaking strength of whole bones with no difference between the CLO and non-CLO hens. However, the density and breaking strength of the bones of the non-CLO hens were consistently greater than those of the CLO hens. The density and breaking strength of the bones of both groups of birds increased with age.