Most layer farms consist of cage systems. Battery cages are the most used systems. However, especially in western countries society put forward more and more objections to the use of traditional cage systems. Animal welfare is believed to be damaged within these systems and therefore in 2012 they will be forbidden in the whole European Union (regulations). Alternatives for cage systems are welfare cages, aviary-, free range- and ecological or organic systems. Each system has its own problems regarding food safety. Many of the issues are listed for GPS already
Traditional cage system
Chicken are housed in metal cages. Several levels of laying hens are situated above each other. One cage contains 3 to 5 chickens. Bottom of the cage has a slope in order to let the egg roll to the front where they can be collected either by hand or through an egg belt. Feed and water are automatically supplied. Manure either falls in deep pits or is removed by manure belts.
Food safety issues:
Layer house normally have natural ventilation, which opens the possibility of introducing insects and other pest animals. Control of rats and mice should be of high standard, and wild birds should not be allowed inside the houses.
Layer cages allow easy control for farmers, although the lower and upper rows of cages are difficult to reach for inspection
Deep pit manure systems may lead to problems with flies and other insects, since the manure stays underneath the cages for a long time. Manure belts are frequently emptied, and the manure is stored outside the housed.
Equipment should preferably stay in the house, and should be maintained and cleaned frequently.
Cleaning and disinfection
During the long lasting rounds, cleaning and disinfection of facilities such as feed and water systems and egg conveyer belts is practically impossible. However there is an urgent need for keeping them clean and free of dust. Regular dust cleaning should be done.
In welfare cages chicken have more space than in the traditional cage systems. Welfare cages also contain laying nests, litter-places and sit-stocks, so chicken can practice natural behavior. Also rules for enough water and feed supply are stated. The addition of these tools makes the cages more complicated and thus susceptible for contamination.
Deep litter and Aviary system
In deep litter systems hens are kept inside the house, but have access to the entire house. The floor is often divided in two: half is deep litter with a bedding material and the other half is a grit system with a manure pit underneath.
Aviary systems are in-between cage- and deep-litter systems. Chicken can walk around freely, however in contradiction with a deep-litter system it consists of more levels. The floor consists of litter and the levels of metal grits. Manure under the levels is automatically removed with manure belts.
Many of the public health and animal health issues are listed for GPS already.
On top of these ground eggs have to be removed frequently and kept separate from the rest. Washing or cleaning of these eggs should be avoided since contamination of contents may occur, which leads to spoiled eggs in retail.
Ecological or Organic farming
In organic or ecological farming hens have access to free range. Additional, there are several rules in relation to food, medicine use and number of chicken per m2 that apply in ecological farming. Rondeel is a recent development in ecological and welfare of keeping layers. The following link shows an impression of this system.
Food safety issues:
Many of the issues are listed for GPS already, but there are some additional facts that need to be addressed:
· Often the organic farming leads to lower hygiene standards, since the animals are allowed outside, which opens the possibility for undesired guests to enter the house. Moreover the hens can come in contact with infectious agents in the direct environment of the house
· Since drugs are only allowed occasionally, diseases must be avoided according to the prevention theory. Selection of animal species that are adapted to the environment is preferred above the use of medicines.
· Organic farms are often small scale operations, so the need for presence of more ages or more flocks on site is more common than in traditional poultry farming.
· Chicken have the opportunity to walk around freely on the floor. Feed is supplied on the floor and water cups are also situated near by the floor. In free range systems chicken can go outside. Deep-litter systems are only inside.