The high prevalence of fractures observed in hens during the production period, in flock replacement and transport is indicative of osteoporosis in laying hens as a normal phenomenon. Osteoporosis is characterized by a progressive loss of mineralization of structural skeleton bones, their fragility and increased susceptibility to fracture. Spontaneous fractures, including spinal fractures and death, occur with a large decrease in structural bone strength. The extended laying cycle reduces the possibility of bone regeneration and increases the incidence of fractures. In all breeding systems, from cages, aviaries to litter, relatively frequent fractures of the breast bone occur. In addition to nutrition, this is influenced by genotype and housing.