LAYING CAGE SYSTEM

Laying cages are the most common method of commercial egg production in the UK - representing around 80% of eggs sold in 1997. They offer a high degree of control over the bird's environment and hygiene. There are also good opportunities for mechanisation of routine operations such as the provision of feed and water and the removal of droppings.

Between three and five birds are kept in each communal cage. An EU Directive sets a minimum requirement of 450 sq cm per bird. UK regulations set higher space requirements for less than four birds in a cage:

Typically a laying cage system consists of a series of at least three tiers of cages. The cages have sloping mesh floors so that the eggs roll forward out of the reach of the birds to await collection. Droppings pass through the mesh floors onto boards, belts, the floors of the house or into a pit to await removal.

Food is supplied in troughs fitted to the cage fronts and an automatic water supply is provided. The units are kept at an even temperature and are well ventilated. Electric lighting provides an optimum day length throughout the year.

All cage units are fitted with alarms that will ring if any of the ventilation equipment fails. Alternative ways of feeding and of maintaining a satisfactory environment are available in the event of a breakdown.

Pro's
- Easy to control environment eg temperature, feed, water and light
- Space restriction suppresses hen aggression
- Small hen colony size
- Good disease control
- No threat from predators
Cons
- Lack of space/facilities prevents certain normal behaviour eg dust bathing
- Cage structure may cause feather and foot damage
- Confinement leads to weak bones and bone breakages

BARN SYSTEM

Around 5% of eggs sold in the UK are produced in the barn system.

In the barn system the hen house has a series of perches and feeders at different levels. The European Egg Marketing Regulations stipulate a maximum stocking density of 25 hens per m² of floor space. Perches for the birds must be installed to allow 15 cm of perch per hen.

In the deep litter system the birds are kept in hen houses in which all the floor area should be solid with a litter of straw, wood shavings, sand or turf. The maximum permissible stocking density for the deep litter system is 7 birds per square metre.

In both systems one nest box per five birds or communal nests, at the rate of 120 birds/m² of floor area of communal nest, are provided. Water and feeding troughs are raised so that the specially prepared food is not scattered. Natural lighting may be supplemented by electric lighting to provide an optimum day length throughout the year. At the end of the laying period the house is completely cleared and disinfected.

Pro's
- Varied physical environment where normal behaviour can be expressed
- Protection against predators
- Freedom to move within the hen house
- Provision of nest boxes, perches and dust bathing facilities
- Improved bone strength due to increased activity
- Birds can escape aggression by moving within the hen house
Cons
- Beak trimming may be required to prevent bird aggression such as feather pecking and cannibalism
- Management of waste droppings more difficult
- Hens can be injured by falling between perches at different levels
- Increased risks of parasites

The free range system accounts for around 15% of eggs sold in the UK.

The European Egg Marketing Regulations stipulate that for eggs to be termed 'free range', hens must have continuous daytime access to runs which are mainly covered with vegetation and with a maximum stocking density of 1,000 birds per hectare which is 395 birds per acre. The hen house conditions for free range hens must comply with the regulations for birds kept in perchery (barn) systems, or deep litter stocked at 7 birds/m² when no perches are provided.

Pro's
- Freedom to move freely and express wide range of behaviour
- Opportunity to graze on vegetation and varied diet
- Opportunity to dust bathe in soil
- Improved bone strength due to increased activity
Cons
- Beak trimming essential to prevent bird aggression such as feather pecking and cannibalism because of large flock sizes
- Risk of predators
- Disease risk due to access to droppings and contact with wild birds
- Adverse climate outside

GENERAL 

SHADING

To reduce pecking risk, avoid high light intensity. Shading can be achieved by painting the windows, avoiding reflective ceilings, using screens (blinds) to avoid direct sunlight morning and evening and using sliding shutters to control light inside the house according to season.

POSITIONING

The building should be oriented to avoid the entry of sunlight at dawn and evening. An East-West siting for litter houses is best if you have automatic ventilation.

For free range houses in a South West/North East orientation a wind break may be necessary.

LIGHTING

Lighting should preferably be by incandescent bulbs that spread the light more evenly. The lights should have shades.

If the lighting is by neon tubes these should be sufficient in number of a warm colour and controllable intensity.

Nests should be in the shade. Where half floor/half slats are used, have the floor well lit to avoid floor eggs. It is possible to improve the light distribution by covering tubes with adhesive tape (scotch tape) in blue or red.  

REARING CONDITIONS

Birds must be reared in buildings that allow the use of a light pattern and control of light intensity.

Rearing for floor production must be on litter in buildings equipped with the same system of drinkers and feeders which will be used in the laying house. Birds will adapt better to the use of slats and nest perches in the laying house if perches are provided in the rearing house.

The light intensity must be sufficient (30 to 40 lux) to avoid over stimulation when transferred if production is in a naturally lit house.  

SLATS

The height between floor and slats must not be greater than 60 cm. Greater height than this will lead to floor eggs. Access to the slats can be improved with the use of ladders. Make sure birds do not smother under the ladders.

At transfer, spread a little straw on top of the slats to encourage use by the birds.

INSIDE WALK WAYS

Inside walk ways in half litter/half slat houses must have ample deep litter. Regular distribution of grit will make the birds work the litter and discourage floor laying by eliminating nest making in the litter.

OUTSIDE WALK WAYS

It is important 'walk ways' are well drained. Puddles must be avoided to limit the risk of colibacillosis contamination that affects shell colour. The immediate surround of the house should be gravel. Rain gutters are essential.

The area immediately alongside the house should be well drained. We recommend installing a drain about 2 meters from the house wall. Rainwater gutters and downpipes should be large enough to remove rainwater.

It will encourage the birds to go out if access ramps are provided outside the pop holes, and if the run area is wooded. That will encourage the birds to feel that they have a refuge from predators and protection from the sun's rays.

The run should be fenced with two strands of electrified wire at 15 and 40 cm from the ground to protect from foxes. An electric fence a few meters from the building will prevent domestic animals getting close to the building and will reduce the risks of smothering.

DENSITY

Stocking density should not be more than 7 birds per usable m2 in litter house and should not be greater than 10 birds per usable m2 in slatted houses. The use of perches is advised when bird density is high.

VENTILATION

Ventilation should be used as a major management tool to provide the optimum micro-environment per bird. Controlled ventilation can do a great deal to dilute pathogenic organisms as well as provide an optimum micro-environment when ventilation equipment is designed and operated to give correct air speed and direction.

The birds optimum environmental temperature should be in the range 21-27⁰C (70-80⁰F) with a relative humidity between 40-60%.

FEEDING

Allow 10 cm of linear feeder per bird or I tube feeder per 20 birds. One round drinker for every 100 birds in a temperate climate or 70 in hot climates. The height of feeders and drinkers do not impede bird movement nor encourage floor laying under them.  

Floor mounted chain: is the preferred system since it is easily emptied avoiding accumulation of dusty feed.

Setting of tube feeders: the adjustment of feed depth must allow the feeder to be emptied completely. A correctly programmed timer will leave the system empty at early afternoon. This equipment is not recommended in hot climates.

Distribution by aerially mounted pipe: not recommended as system cannot be emptied and leads to low feed intake.

Any system which cannot be emptied and does not allow even and fast distribution of feed on is strongly inadvised.

PERCHES

Perches reduce aggressiveness and allow a higher stocking density. The following minimum space per bird is suggested:

The perches should be situated on the slats to maintain good litter condition.

Distance between perches should be 40 cm and a slope of 45°.

NESTS

The general recommendation is for one nest per 5-6 birds. Nests should be placed in shaded areas at one or two levels. At the start of production nests should contain straw to reduce floor eggs (see floor laying).

ELECTRIC FENCE

To reduce the amount of floor laying, an electric fence may be considered. It should be placed around the outside of the litter area 5 cm from the edge of 15 cm above the lifter. It should be switched on during the hours of egg laying in the morning when the lights come on.

HOUSE CONDITIONS