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30

LOHMANN TIERZUCHT

MANAGEMENT GUIDE

30

The principle for windowless houses

“Do not increase the hours of light during

rearing period and do not reduce hours

of light during production period”

also

applies to “open” houses.

The effect of the natural daylight must be

considered when designing lighting pro-

grammes, if natural light enters the building

throughout the day or if the hens have free

access to open-air runs.

For example in Central Europe the natural

day length increases in the course of the cal-

endar year to about 17 hours until late June

and then shortens to about 8 hours until late

December.

If flocks are moved to an open production

house with windows that cannot be dark-

ened, the lighting programme must be ad-

justed to the natural day length at the time

of rehousing.

We distinguish between two variants:

1.

Production starts as the natural day

length decreases.

2.

Production starts as the natural day

length increases.

In both variations the lighting programme at

17 weeks of age should be set to a lighting

period of at least 10 hours, taking the natural

day length into account, and to be increased

by 1 hour every week to 14 hours until 21

weeks of age.

Never switch on the artificial light before

04.00 o’clock in the morning (CE time).

During the spring months the lighting pro-

gramme is affected by the increase of natural

day length and gradually extends to about

17 hours. When the natural day length be-

gins to decrease in Central Europe from

July, the 17-hour light period should be kept

constantly until the end of the production

period.

This example can be accomplished in Central

Europe very simply as follows:

04.00* o’clock in the morning: lights on –

dimmer switch off at ≥ 50–60 Lux.

Dimmer switch on at ≤  50–60 Lux–

21.00 * o’clock in the evening lights off.

* Central European time

These times should be varied depending on

the condition of the flocks, the start of lay

(production, egg size) and the facilities in the

building.

If for operational reasons a different diurnal

rhythm from the one described above is

applied, it should not differ too much from

the dawn/dusk times stated above, having

regard to the diurnal rhythm of the hens.

Lighting Programme for Open Houses