MANAGEMENT OF LIGHT FOR POULTRY 

Pashu Sandesh, 15 Feb 2023

Dr Vikash Bhardwaj¹, Sonam Bhardwaj², and Dr Ragini Mishra³

The management of lighting systems is an essential component of the production of poultry. There is a correlation between the amount of light and the performance of birds. Because birds are so sensitive to light, it has an effect on their growth, sexual maturity, feed consumption, egg weight, egg quality, and egg output. When laying begins at an excessively young age, the hen produces eggs that are smaller in size and, from the perspective of the producer, have less value. When reproduction is postponed until a later age, the resulting eggs are larger in size. From a financial point of view, its value is significantly higher. The activity of the hypothalamus is increased in response to light through the eye. The anterior pituitary gland is responsible for the secretion of follicle-stimulating hormone and luteinizing hormone. This hormone improves the function of both the ovary and the oviduct. It regulates the development and maturation of the follicle and boosts the production of the steroid hormone. Light can also have an effect on oviposition that has been triggered by oxytocin.

To regulate the pullets' maturation at the appropriate time, it is essential to maintain control of the lighting conditions they are subjected to while they are growing. The duration of light, the strength of light, and the different colours of light can all have an effect on the performance of birds. The impact of each indi-vidual component will be covered in this section.

PHOTOPERIOD (DURATION OF LIGHT)

In a grower, the least amount of time that effective light must be present is between 9 and 10 hours. If you do not want the influence of the length of light to be present (for example, in growing programs), the photoperiod should be less than 9 hours. On the other hand, if the effect of the light period is something that is desired, the photoperiod must be longer than 10 hours. The age at which poultry becomes sexually mature can be lowered by extending the length of the photoperiod, while it can be raised by shortening the length of the photoperiod. The size of the egg will also rise as a result of this. During the first year of laying eggs, the total number of eggs produced often increases. There is a window of opportunity to lay eggs that lasts for 14 hours. From the age of 21 weeks, the light duration should be increased by 30 minutes every week, going from 14 to 17 hours. During the laying stage, it is undesirable to have a photoperiod that is longer than 17 hours.

The only way to lengthen or shorten the amount of daylight in houses with their environments carefully managed is to employ artificial light. It is necessary to complement the natural light that enters open-sided houses with artificial light. Because the hours of dawn and sunset differ from one location to another and from one season to the next, the natural light does too. Growers don't require any more light when they're working in residences with open sides.

Evening, morning, or both times of day can have artificial light added to open-sided houses for layers. It is agreed upon that the light will be switched on and off at predetermined intervals. It is more practicable and advantageous in day-to-day farm operations to provide light to laying birds both in the morning and in the evening.

 INTENSITY OF LIGHT

The minimum acceptable light intensity for birds is around 0.04-foot candles. In regular use, there is an intensity of a one-foot candle provided for the light. The light intensity of natural daylight is significantly higher than that of a single-foot candle. In a cage design, the birds receive less light at lower tiers and more light at higher tiers. Higher light intensities are not ideal for layer birds but can be damaging to growing birds. A light metre or a candela can be used to measure the amount of light present. The term "candela intensity" refers to the unit of light intensity that is calculated based on the ratio of one foot of height to one square foot of area. The rate at which light falls on an area of one square foot from a height of one foot is measured in lumens. The average incandescent bulb emits 12.56 lumens while only consuming one watt of power.

The birds do not have access to the full amount of light supplied by the lights. The walls, ceilings, and other equipment in a poultry house typically absorb 30% of the available light. The dirtiness of the bulb reduces the amount of light that it emits by 30%. This means that just 49% of the total lumen may be used (6.15 lumen from one watt.). Flat-type bulb reflectors are typically utilised in poultry houses so that light can be delivered to the birds in an unobstructed manner. Light output from clean bulbs is at its maximum level. The amount of light produced by dusty bulbs is diminished.

COLOUR OF LIGHT

There is a correlation between the colour of the light and the production of birds. White light is utilised most. Orange or red light might be employed in the poultry farm every once in a while. The height between the bird and the bulb should be approximately 7-8 feet. The light that is distributed more evenly can be achieved using bulbs that have 60 watts or less. In poultry buildings, the bulbs are typically organised into rows. It is recommended to leave a distance of 6 feet between the outside rows of bulbs and the side wall. It is recommended that there be a distance of 12 feet between each bulb in a row. On average, 1 watt is required for every 4 square feet of floor space in order to achieve the same level of illumination as a foot candle.

DIFFERENT TYPES OF LIGHTING PROGRAMMES

Depending on the type of housing, such as open sides or environmentally controlled ones, there are a variety of lighting programmes accessible to choose from. Beginning on June 21, which is the day with the longest photoperiod of the year, the duration of light will continue to shorten until December 21, after which it will begin to lengthen again until June 21. In houses with open sides, this can be accomplished in three different ways:

I. STEP-DOWN (NATURAL) STEP-UP SYSTEM

Pullets hatched between March 29 and August 3 are exposed to decreased photoperiod during the growing period (12-20 weeks). The duration of light should be increased to 17 hours by half an hour per week from 21 weeks of age.

II.   STEP-DOWN (ARTIFICIAL) STEP-UP SYSTEM 

In this, chicks hatched between August 4 and March 28, are exposed to increase natural light during the growing period. Duration of light is decreased by 20 minutes per week from the chick stage and light duration is increased at 21 weeks of age from 13 to 17 hours by half an hour per week.

III. CONSTANT AND STEP-UP SYSTEM

Grower birds are kept in constant light periods. Laying birds are provided 16-17 hours of light.

LIGHT FOR BROILERS

The light intensity may be about 0.5-foot candle at bird level, providing full light for 3 weeks during brooding. Then reduce the duration of light.

LIGHT FOR QUAIL

Full light may be provided during brooding and rearing for early sexual maturity. Otherwise, 12 hours of light and 12 hours of darkness may be provided during the rearing period. 8 hours of light and 16 hours of darkness are desirable for finishing birds.

Dr Vikash Bhardwaj¹ (PhD Scholar - Division of Poultry Science)

Dr Sonam Bhardwaj² (PhD Scholar- Division of Livestock Production and Management)

Dr Ragini Mishra³ (PhD Scholar- Division of Veterinary Microbiology)

ICAR-CARI and ICAR-IVRI, Izatnagar-243122, Bareilly (U.P.)