About 80% of eggs purchased in Australia are cage eggs. These eggs come from hens that are housed in cages within a shed. Cage typically accommodates between four and twenty birds and range in size from 1800cm² to 11,000cm².
Government, animal welfare groups and the egg industry have agreed to improvements in animal welfare, which includes increasing the minimum space allowance for hens in cages to 550cm² per bird.
Hens in this system have the following welfare advantages:
- Protection from the elements and predators like eagles, snakes, foxes and feral cats.
- Lower occurrences of manure-borne diseases and parasites. Of all the production methods, health issues and hen mortalities are consistently the lowest in cage systems.
- Reduced need for veterinary medications and interventions, thereby minimising stress associated with bird handling.
- If a bird does become sick, cage-based housing makes it easier to identify and remove birds for treatment.
- Modern cage housing reduces the risk of disease such as avian influenza and other exotic diseases.
- Better protection from in-fighting and cannibalism.
Disadvantages include:
- Reduced social interaction with other birds.
- Considerably less space to roam, but enough space to stand upright and stretch their wings.
- Inability to display natural behaviours like nesting and dust-bathing in most cages.
Conventional cages do not allow hens to perch which can result in lower bone strength and increased bone breakage during removal of hens at the end of lay.