Caged hens are particularly prone to bone weakness
The Farm Animal Welfare Council (FAWC) today released their assessment of the causes of osteoporosis and bone fractures in laying hens.
It confirms that a major underlying problem lies with the breeding of hens who lay unnaturally large numbers of eggs, around 300 a year. The calcium needed to produce so many eggs, particularly the shells, results in less calcium being available for their bones leading to osteoporosis and bone weakness.
The report also shows that the problems with osteoporosis and fractures seem to be getting worse rather than better. This is likely to be due to advances in breeding and genetic technology. In 1930 a typical laying hen produced 115 eggs per year. That number is now 300 and is set to rise even further. A hen's metabolism often cannot cope with working that hard and producing that much calcium for the shells of their eggs.
Bone weakness in caged systems
Bone weakness is a particular problem in caged systems which prevent exercise. Walking, hopping, flapping and perching all lead to better bone strength. Battery hens are particularly prone to bone breakage at the end of the hens' laying cycle when they are removed from the cages and transported for slaughter. During this process, caged hens suffer significantly more fractures through having very weak bones and often being roughly handled during catching.
Hens kept in alternative systems are less at risk of bone breakage on the way to slaughter due to their stronger bones. However, they are at high risk of bone fracture due to collisions with the building's furniture.
Solving the problem
This problem will continue to exist in all systems for as long as the industry uses hens who produce unnaturally large numbers of eggs. The report suggested that aerial perches should be provided, subject to improvements in design which reduce the risk of collisions which cause fractures. Flying up to a perch is good for bone strength. Perches also enable hens to express normal behaviours and play a vital part in reducing the risk of injurious pecking in a flock and therefore the need to beak trim.
Compassion believes that we should breed hens to produce modest numbers of eggs and keep them in non-caged systems with aerial perches that meet their health and welfare needs.