How to scientifically control lighting in enclosed laying hen houses?

Scientific and rational supplemental lighting not only promotes the normal development of laying hens and reduces morbidity and mortality, but also extends the laying period and increases egg production, which helps improve the economic returns of laying hen farming. Conversely, improper lighting leads to poor development of laying hens, causing them to start laying too early or too late, which not only affects the laying rate and egg production throughout the entire laying period, but also increases the morbidity and mortality of laying hens, causing huge economic losses to farmers. The lighting control techniques for enclosed laying hen houses are introduced below for reference.

?I. Lighting duration control

1. Brooding period (0-6 weeks of age). Lighting is very important for chicks' feeding, drinking, movement and health, but if the lighting duration is too long, chicks will reach sexual maturity too early, affecting their later laying performance; if the lighting duration is too short, it will affect the chicks' activity and feeding, leading to stunted development. Generally, during the first three days after hatching, 23 hours of light and 1 hour of darkness are provided, so that the chicks adapt to a dark environment and avoid panic in case of a power outage; after 4 days of age, lighting is reduced by 30 minutes per day, until at 14 days of age the lighting duration is reduced to 18 hours; starting from 15 days of age, lighting is reduced by 2 hours per week, until at the end of 6 weeks of age the lighting duration is reduced to 10 hours.

2. Growing period (7-20 weeks of age). If the lighting duration is too long during this period, it will promote premature sexual maturity of laying hens; if the lighting duration is too short, it can lead to delayed sexual maturity, obesity, large egg weight at the start of laying, high rates of difficult laying and mortality, and reduced total egg production. Therefore, 10 hours of light are provided from 7 to 17 weeks of age, and starting from 18 weeks of age, lighting is increased by 1 hour per week, reaching 12 hours at 20 weeks of age.

3. Laying period (21 weeks of age to culling).

Increasing the lighting duration during the laying period can stimulate the secretion of sex hormones in laying hens and promote egg laying, but too long an increase will lead to an increased egg breakage rate; conversely, reducing the lighting duration will inhibit the secretion of sex hormones in laying hens and reduce egg laying. Therefore, the lighting duration during the laying period should adopt a gradual increase method, that is, starting from 21 weeks of age, lighting is increased by 30 minutes per week, reaching 16 hours at the peak laying period, after which 16 hours of light are maintained, and near the culling period (about 59 weeks of age) lighting is increased by another 30 minutes per week, until reaching 17 hours.

?II. Lighting intensity control

1. Brooding period (0-6 weeks of age). If the light is too intense during this period, it will affect the chicks' nervous function and cause vices such as feather pecking and vent pecking; but if the light is too dim, it is inconvenient for the chicks to feed and drink. Generally, during the first three days or the first week, the light intensity can be somewhat higher, using 20-25 lux (an incandescent bulb providing 0.16 watts per sq m of lighting equals 1 lux); afterwards, as the age in days increases, the light intensity gradually decreases, and 5-10 lux is sufficient at the end of 6 weeks of age.

2. Growing period (7-20 weeks of age). If the light is too intense during this period, it will make growing chickens restless, causing pecking vices, prolapse and nervousness; but if the light is too dim, it will reduce the feed intake and water consumption of growing chickens, leading to poor growth and development and delaying the start of laying. The light intensity during the growing period should preferably be 5-10 lux.

3. Laying period (21 weeks of age to culling).

If the light intensity is too high during this period, it not only wastes electricity, but also makes laying hens restless, causing nervousness, easy startling of the flock, and prone to fighting, pecking vices and prolapse; if the light intensity is too low, it will not have a stimulating effect on laying hens, thereby affecting egg production. Generally, the light intensity during the laying period should preferably be 10-20 lux.

????III. Selection of light color

The chicken hypothalamus contains extraretinal photoreceptors, and these photoreceptors respond differently to light stimulation of different wavelengths. Red light is unfavorable for the growth and development of chicks and growing chickens, delaying their sexual maturity, but it is beneficial for laying hens, making them quieter, increasing egg production and reducing pecking vices; green light can accelerate weight gain in chicks and advance sexual maturity in growing chickens with delayed growth and development, but it inhibits egg laying in laying hens and reduces their egg production; although yellow light can increase egg weight in laying hens, it leads to delayed sexual maturity in growing chickens and a higher incidence of pecking vices in laying hens; blue light easily induces pecking vices and reduces the laying rate and disease resistance of laying hens. Therefore, incandescent bulbs or high-efficiency energy-saving lamps should be selected in production; the wavelength of this light source is between 500-625 microns, which includes light of various wavelengths such as red, orange, yellow and green, and can meet the lighting needs of laying hens at different stages without producing side effects.

????IV. Summary

1. Lighting control must be coordinated with a standardized feeding management system, such as providing full-price compound feed and sufficient clean drinking water, maintaining a suitable house environment, and adopting comprehensive epidemic prevention measures, so as to achieve the expected results.

2. Lighting control must be combined with actual production, and appropriately adjusted according to seasonal climate, laying hen breed, feeding and management conditions, etc. For laying hens whose average body weight is below or above the standard body weight, the time for increasing lighting should be appropriately delayed or advanced.

3. Chicken farms (households) with the necessary conditions can use poultry house light controllers such as the DF-24 programmable timer controller to achieve automatic turning on and off of lights, which not only ensures accurate lighting duration, but also helps stabilize light intensity and provides a gradual transition between light and dark.