Light stimulation is important for egg production in layers. The length and intensity of light received by birds daily impacts egg production, growth, and physiology. Light stimulates the pituitary gland to release hormones that regulate sexual maturity and egg laying. During the growing period, decreasing light hours can delay sexual maturity by up to 3 weeks. During the laying period, a minimum of 16 hours of light per day is needed for maximum egg production. Proper light management through intensity, duration, placement and cleaning of bulbs is important for bird health and productivity.

1. Light stimulation and sexual maturity in layers
• Md. Jakir Hossain
• Id: 19PS JJ-23M
baujakir@gmail.com
+8801789-705507
• Department of poultry Science
• Bangladesh Agricultural University

2. •What is lighting?
• The egg production, growth ,normal
physiology is associated with the length
and intensity of the light received by the
bird daily.
• Wavelength and intensity is important
in lighting.
• Lighting period also important.

3. Types of lighting
Natural lightingArtificial lighting

4. • Artificial lighting
• Incandescent:
• Cheapest ,short bulb life (750-1000 hrs)
• Fluorescent:
• 3 to 4 times more efficient than
incandescent bulbs.
• Mercury vapour:
• Long life (24,000 hrs), requires several
minutes to warm up, cannot be used in
houses with low ceilings.
• Compact Fluorescent (CF) Lighting:
• More energy efficient. One-fifth energy of
fluorescent light is needed to provide same
light intensity (lumen).
incandescent Fluorescent
Mercury vapour CF lighting

5. Purpose of lighting
Adequate lighting in poultry houses is
essential.
To be able to identify weak or infected
birds.
For a good feeding environment.
Good designs for happy birds.
Dusk to dawn stimulators essential.
Dimming essential.
To maintain good hygiene – cleaning /
washing.
To satisfy requirements

6. Lighting and sexual maturity
length and intensity of the light is
connected, received by the bird daily.
Light stimulates the anterior lobe of the
pituitary gland through optic nerve for
the release of FSH and LH.
Light energy also penetrates through
the skull, skin and feathers.
 FSH increases the growth of the
ovarian follicles. Upon reaching
maturity, the ovum is released by the
action of LH.

7. Light effects during growing period
Decreasing the length of light day during
growing period will lead to
• Increase the age at sexual maturity
• Increase the number of eggs laid during the
first half of the egg production (but not in
total number of eggs laid)
• Increase the size of the first eggs produced.
• Light restriction alone delays the sexual
maturity at the maximum of 3 weeks.

8. Light effects during laying period
o Birds reared under increased day-light produce more
eggs due to the release of FSH and LH from the
pituitary.
o Brightness of light also has influence on egg
production. On practical conditions, 1 ft candle light
intensity is needed in layer houses. In multi-deck cage
system, minimum of 0.5 foot candle light intensity is
needed at the lower deck.
oFor maximum egg production, 16 hours light is needed
during peak egg production period.
o Reducing photoperiod during laying period seriously
affects egg production.
o The artificial light can be given either in the morning,
evening or both morning and evening.

9. Lighting requirement graph and chart
Age(week) Light
intensity(lux)
Photo period(hours of
light)
20-72 10-30 Increase 30 minute per
week(upto 16-17 hour)

10. • Light management
o Efficiency is related with light.
o The distance between bulbs should be 1½ times the
distance from the bulb to the bird level.
o The distance from the bulbs to the outer edges of the
house should be only ½ the distance between bulbs.
o In cage system, the bulbs should be placed in such a way
that their rays fall on the feed and on the birds.
o Clean reflectors increase the light intensity at bird level by
50%, compared with no reflector.
o Avoid cone shape , Better to use flat type reflector with
rounded edge.
o In case of deep litter system, the bulb is to be placed at 7-
8’ height whereas in cage house.
o Avoid hanging bulbs by a cord in open houses
o Light bulbs should be cleaned once in two weeks.