The Laying Hen Welfare Working Group of the Global Coalition for Animal Welfare (GCAW) has published a formal position on combination systems for laying hens.
Combination systems for laying hens, also known as combi-cages, convertible housing systems or ‘lock-back’ cages, are a type of production system for laying hens that can be operated as either a cage or cage-free system. They are similar in appearance to multi-tier aviary systems but have flaps or doors which can be closed to confine the hens within the tiers, temporarily or permanently. When operated with the doors in the closed position, these systems have the same negative impacts on laying hen welfare as caged production systems.
Unlike multi-tier aviary systems, combination systems typically have partitions within the tiers and an absence of ramps between tiers, which restricts the movement of the hens within the system, even when operated with the doors open. The main impact on welfare, whether operated as a cage or cage-free system, is a restriction of the behavioural freedom of the birds.
Combination systems are a relatively new development in the industry and, as such, it is not clear how they are addressed by legislation. It is currently difficult for food companies to monitor and avoid the use of combination systems within their cage-free egg supply chains.
There is limited information available on the prevalence of combination systems, but they are present in Italy, Spain and the US, in addition to other countries. However, in the UK, the British Egg Industry Council has prohibited the use of combination systems within its industry standard for barn eggs.
Combination systems for laying hens, also known as combi-cages, convertible housing systems or ‘lock-back’ cages, are not regarded as truly ‘cage-free’, as such systems combine aspects of conventional cages and multi-tiered aviaries. In a ‘doors closed’ position, hens are confined to cages and the system reverts to being a cage system. GCAW does not consider the use of combination systems as compatible with corporate cage-free egg commitments.
The formal position can be found here: GCAW Position on Combination Systems