Artificial LIGHTING W. O. Wilson W. F. Rooney R. E. Pfost J. R. Tovernetti CALIFORNIA AGRICULTURAL Experiment Station Extension Service CIRCULAR 5 29 ARTIFICIAL LIGHTING FOR POULTRY This circular briefly discusses the biological responses of chickens and turkeys to light, and describes proper light- ing systems for poultry of various ages. OCTOBER, 1964 THE AUTHORS: W. O. Wilson is Professor of Poultry Physiology in the Experiment Station, Davis; W. F. Rooney is Poultry Specialist in the Agricultural Extension Service, Davis; R. E. Pfost is Farm Advisor in the Agricultural Extension Service, Fresno County; J. R. Tavernetti is Agricultural Engineer in the Experiment Station, Davis. Glossary Foot-candle — the intensity of light 1 foot away from a standard candle. A standard candle is approximately the same as a common candle of 1-inch diameter. Lumen — a unit of quantity of light emitted by a light source or striking a surface. A standard candle emits 12.57 lumens. One lumen per square foot of area will produce a light intensity of 1 foot-candle. Effect on poultry \_j hickens and turkeys normally hatch Intensity of Light in the spring, mature during summer and fall, and start to reproduce the following Needed by Poultry spring. Under natural conditions sunlight _, , , . , , , , .,, , is the only light available, and therefore Both chickens and turkeys will produce birds hatched in the spring develop on e gg? whe T n h 8 ht ln , te " slt y ls 2 foot-c^* . _. . r S f. i . S or less. Laying turkeys reqmre 2 toot- mcreasing amounts or daylight as days ,, , (. ,° i_.i i • r i n u P . toitju* candles or light, while chickens lay well become longer up to Tune 21. By about L , f 6 ' . L . L . , J •j a _ ■ _ j „ ui at a 1 root-candle intensity. A clear noon mid- August, when days are noticeably J shorter, chickens are fully grown and tur- keys almost so, but gradually decreasing Table 1. Various Light Intensities amounts of daylight are unfavorable for Affecting Poultry egg production; nature, while providing ______ for the preservation of the species, does Li ht not consider the consumer and the poul- intensity try producer. Thus, to obtain good egg candles) production as days shorten, poultrymen must use artificial lighting. Added light ° 01 can simulate lengthening days or com- 05 pensate for decreasing amounts of natural light. Diminishing daylengths encourage growth of adolescent poultry, however. 10 Light acts as a powerful stimulus to poultry. It greatly influences sexual ma- turity (the time when females begin to 20 lay and males begin to produce sperma- tozoa) and subsequent egg production in the females and semen production in the in mid-summer may provide up to 10,000 male. Light also acts as a signal to govern foot-candles of light, while an overcast the time of day eggs are laid. Birds are noon may range from 100 to 1,000 foot- more stimulated by light near the red end candles in intensity; bright moonlight of the spectrum than by light in the green, measures about 0.02 foot-candles, and blue or violet regions. Light from almost colors merge into grey, for the human any commercially produced bulb or tube eye, at an intensity of about 0.01 foot- will be satisfactory for such stimulation, candles. provided that intensity and duration of Sexual maturity may be retarded by light are controlled. subjecting poultry to semi-darkness for Retards sexual maturity in chickens and turkeys. If light intensity is increasing (as at sun- up), chickens will leave roost at about this point. If light intensity is decreasing (as at sun- down) chickens will go to roost at about this point. Light at this intensity is suit- able for laying chickens. Suitable light for laying turkeys. considerable parts of the day in specially the day, as shown in table 2. (See Cali- constructed houses in which light inten- fornia Agricultural Experiment Station sity can be reduced to 0.01 foot-candles Extension Service Circular 526, "Light or less, but light intensity of 0.5 foot-can- and Temperature Controlled Housing for dies or more should be used for part of Poultry.") Table 2 Recommended Methods of Lighting Chickens and Turkeys Age of birds (weeks) Minimum light (foot-candles) Light-to-dark ratio (hours) Method 1 Method 2 Method 3 Replacement pullets for egg production 0-3 1.0 0.1 to 0.5 20:4 hours Seasonal daylight 20:4 hours Decreasing at rate of 15 to 30 minutes per week 20:4 hours 3-12 16:8 hours 12-21 0.5 Seasonal daylight, if decreasing; otherwise, short day lengths 6:18 or 8:16 hours Continue with simu- lated decreasing day- lengths Continue 16:8 to 16 weeks of age, then give 8:16 until 21 weeks Commercial chicken layers 1.0 Seasonal light if in- creasing, or 16:8 or 15:9 hours, depending on latitude Increasing at rate of 15 minutes per week 16:8 hours Parent stock chicken breeders 24-26 or over 1.0 As above As above 16:8 hours Chicken fryers 0-3 1.0 0.1 to 0.5 20:4 hours 20:4 hours 20:4 hours Seasonal daylight and intermittent night light 1:3 hours 20:4 hours 3 until marketed . . Seasonal daylight and intermittent night light 1:2 or 2:2 hours Turkey meat birds 0-3 2.0 1.0 20:4 hours Seasonal daylight 20:4 hours Seasonal daylight and intermittent night light 1 :4 hours 20:4 hours 3 until marketed. . Artificial light decreas- ing at rate of 15 to 30 minutes per week Breeder turkeys 0-3 2.0 1.0 20:4 hours Seasonal declining daylight 20:4 hours Seasonal daylight 20:4 hours 3-8 20:4 hours 8-28 1.0 Naturally declining day lengths 6:18 or 8:16 Artificial light decreas- ing at rate of 30 minutes per week from age 8 to 28 weeks. 2.0 14:10 16:8 16:8 LIGHTING METHODS Four main programs of lighting poultry houses are now used, and several modifi- cations of each are possible. Methods are (1) a large number of hours of light per day, or (2) a constant short daylength, or (3) simulated decreases in daylength, or (4) intermittent light. Table 2 explains how to use these methods. The ratio of light to dark periods is not as important as the change resulting from increasing or decreasing amounts of light. • Large number of hours of light per day. Good egg production has been ob- tained from chickens given 16 hours of light per day for the first 16 weeks, then 9 hours until birds are 22 weeks old, and then 16 hours again. Constant light from 14 to 16 hours per day is commonly used for chickens and turkeys during laying periods. • Constant daylength of less than 10 hours. This method may increase the quantity of eggs but egg size is usually slightly decreased. This special prelay light treatment is recommended for chick- ens hatched from October through March. Short, constant daylengths of 6 to 9 hours after 3 weeks of age and before 14 weeks of age will prevent the chickens from ma- turing too early, which would result in lowered egg production. Contrary to pop- ular belief, short daylengths alone do not delay sexual maturity. Restriction of light during the growing period was tested in Santa Clara County on 2400 February-hatched Leghorn pul- lets during 1960-61. At 8 weeks of age half of the pullets were placed in an arti- ficially darkened evaporatively-cooled growing unit and restricted to 8 hours of light until they were 12 weeks old, and then to 6 hours until they were 20 weeks old. The other half of the flock served as controls, and were reared in a similar house under normal daylength conditions. At 20 weeks of age both groups were placed in an open wire-floored laying house and maintained on 14 hours of light daily. The pullets raised on restricted light laid 40 more cases of eggs from 20 weeks to 17 months of age than did the controls. Egg production at 6 months of age was 62 per cent for the controls, as compared to 76 per cent for the group reared on restricted light. Total eggs per pullet averaged 192.5 for the controls and 205.0 for the light-restricted groups. Mortality was 8.0 per cent for controls, and 5.6 per cent for the light-restricted group. • Simulated decreases in daylength. This is also known as the "step-down" system of light. Chicken pullets are given 20 to 22 hours of light for their first week of life and this is decreased 15 to 30 min- utes weekly, until all light received is natural daylength. When chickens are 20 to 22 weeks old, total reduction of light ranges from 5 to 7 hours, depending on seasonal differences in daylengths. Obvi- ously, step-down lighting occurs naturally when pullets mature in the fall. Special housing is not required because artificial light supplements daylight in an undark- end house. This method results in delayed sexual maturity, improved egg size and good egg production. It is particularly suited for production of large eggs; the chief dis- advantage is the labor of setting clocks frequently. Decreasing daylengths for mature hens can easily reduce lay, but it is doubtful if increasing daylength after several months of laying results in greater egg production. To use this method: (1) Consult table 3 to find daylength when pullets will be 20 weeks of age, and add 5 hours to that davlength. This will give the hours of light to provide the first week. (2) Once a week for 20 weeks and on the same day each week, decrease daylength 15 minutes, holding constantly at the 21st week; after the 21st week the birds should be put on the layer lighting program (method 2, table 2). Changes in time- switch setting may be made on A.M. and P.M. periods on alternate weeks. • Intermittent light. If less than 12 hours of light are used daily, intermittent light is more effective than continuous light for egg production. However, if the intermit- tent light system is discontinued when once started some hens will stop laying; thus it cannot be recommended for layers. # .2 U C i- o U -o 0) CO c o Q c CO c CO CO _0) _Q 5 a a 1 co M a COM''— i ■» H lO M r- c M« ,— i '^»<-«f<-f , CO©CM'— • — 000:0; 0) CO »003t^fOOOCM05C<»t^»-lM»OCNI©»0-»}<-<*' ^ifllOiOlOOCOtOCONNNNNNNCDtOiOIOlOTf'f'Ji 0> M ■*O>eN^O^t»O«M00Mo■«tlO■^ , OcMcoeo«MOcoocM>o^•^"•-HlO^» , o>0500^>-H«»coco-»t<- CO >0©OCMOM , 03 ^, T -^^HOooococopooeM»ot^O'-* CO <— >'** , -t^CO<0!^>iOtOlO-«*<->*<-*ti"«*<-t | iOlOlO»0»OCOC©©tOt^ o '-3 c3 a « c3 CO bO C o> h3 lONHNNeMHMlONlO'*t , ONM!DOM(»W1 , 1 l >0©COlOC0 35 ©©©-"■•— 'CM COCOCO->*'"©©^ >oO'-icO'*i>o^fMco^t<>cooo>nco^^>oeo^^»OT}<'*i->!ri ^lOiOlO'OiCtOCOOOtONNNtDOOiOlOlO^'t't 1 * 0> 10 iOiot^»«ooot^o>ooooocC'^HOOOO 1-3 OOTtlt^CMCSt^tNOOOOOiOOt^t^lCCM^HCO^-COCMOOOS— 1 ©i— iCOOeN'OeOOCNlOO'— 1 1— i©-*j<.^iiocmiocni»o* &***\ 1 T , *ftPi 1L\ . CHOOSING LIGHTING EQUIPMENT Type of Lamps. Incandescent (common Table 4. Effect of Socket Voltage on Light light bulbs) and fluorescent lamps are Output and Life of Incondescent Lamps commonly used for lighting poultry. Fix- tures for incandescent lamps are relatively simple, trouble-free and inexpensive. Fix- tures for fluorescent lamps are more com- plex and more expensive, as they consist of holders for the light tube, a ballast and (with some types) a starter. The last two items mentioned sometimes cause trouble and have to be replaced. When using in- candescents, light intensity may be in- creased or decreased by using bulbs of different wattage. To change light inten- sity with fluorescent lights, however, the fixture must also be changed, as the bal- last and usually the tube-length is de- signed for a given wattage. Some change in fluorescent-light intensity may be ob- tained by changing the type of light tube even though the wattage is the same. For example, the light output of a 40 -watt deluxe cool white lamp is about 2,100 lumens, as compared to 3,000 lumens for the white or warm white type. Fluorescent lumps are more efficient than incandescent lamps and thus are less expensive to operate. Incandescent lamps must have three or four times more wat- tage than fluorescents to provide the same amount of light. When artificial light is used only a few hours daily to supplement natural light, incandescent lamps may be more economical because of the lower initial cost. When artificial light is the Only light, the lower Operating COSt of * Based on life of l < m hours when operated at rated fluorescents suggests that they be con- sidered, mal 1,000 hours at rated voltage; the light Incandescent lamps, which range in 5- output will be reduced by 24 per cent, volt steps from 110 to 130 volts, generally however, and this means that larger wat- have a rated life of 1,000 hours when tage lamps will be needed for a given operated on their designed voltage, light intensity. The efficiency of incandes- Lamps used on higher-than-designed cent lamps increases with their wattage, voltage give more fight, but their life is but they darken with age and this de- lessened; lamp-life is increased with creases light output. Table 5 gives the lower-than-designed voltage, but light approximate light output in lumens per output is decreased. So-called long-life watt for inside frosted or clear lamps lamps are those with a higher rated volt- (these two types are practically equal in age (usually 130 volts) than the voltage light output). Inside frosted or clear in- on which they will be operated. Table candescents give greater light for a given 4 shows that a 130 volt lamp on a socket wattage than do colored bulbs. The in- voltage of 120 volts will have a life of side frosted lamp gives a more diffused about 3,000 hours as compared to the nor- light with less glare. Rated lamp voltage Socket voltage Per cent of rated light output obtained Life of lamp (hours)* 110 100 105 110 115 120 125 100 105 110 115 120 125 100 105 HO 115 120 125 100 105 110 115 120 125 100 105 110 115 120 125 72 85 100 117 135 156 62 73 86 100 115 134 54 62 75 86 100 115 45 55 64 75 87 100 40 47 56 65 76 88 3,500 110 2,000 110 1,000 110 600 110 350 110 200 115 6,000 115 3,300 115 1,750 115 1,000 115 115 600 350 120 10,000 120 5,750 120 3,000 120 1,750 120 1,000 120 600 125 125 125 17,500 9,500 5,250 125 3,000 125 1,600 125 1,000 130 130 30,000 16,000 130 9,000 130 5,000 130 3,000 130 1,600 Fluorescent lamps are also designed for a given line voltage, usually 118 volts, and voltages below or above the rated voltage affect light ouput and life. Light output changes about 1 per cent for each 1 per cent change in voltage, in contrast to the incandescent lamp, whose light out- put changes about 3 per cent for each 1 per cent change in voltage. Unlike in- candescents, a fluorescent lamp's life is decreased by both low and high voltages. Rated life of fluorescent lamps is generally about 7,500 hours, but the number of times they are turned on and off also affects length of life. As with incandes- cents, light output decreases with age of the lamp. Standard white, warm white, or cool white lamps are recommended. Homeline or deluxe cool white (which give more light in the red end of the spec- trum) are satisfactory, but are less ef- ficient. Lamp Reflectors. Reflectors direct more illumination into a limited area. This lowers the lamp wattage necessary for a given light intensity and results in lower operating cost. The increase in light in- tensity may range from 25 per cent to 200 per cent or more. Automatic Controls for Lights. Time- switches, or a combination of time- switches and photoelectric-cell operated switches, are used to automatically con- trol artificial light. A combination of photoelectric cell and a time-switch saves labor in controlling lights. The time- switch turns the lights on at a set time in the morning and off at a set time in the evening, or the photoelectric cell turns lights off in the morning when daylight Fig. 3: Wiring diagram of photoelectric cell and time-switch combination for automatic control of lights. Table 5. Relative Efficiencies of New Lamps Installation and Maintenance of Lamps Lamps should be installed and cared for so that birds never receive less than the minimum recommended light intensity. Because the light output of lamps de- creases with age and is also decreased by dirt or other foreign matter on the glass, it is necessary that the illumination pro- vided by new clean lamps be greater than the recommended minimum foot-candles (table 6 data make allowance for this). Periodic cleaning and replacement of burned-out or badly darkened lamps is essential for maintaining proper illumina- tion. Lamps should be arranged to minimize shadows cast by any obstructions, they should be easily accessible, and they should have sufficient clearance under- neath for people and equipment. The higher the lamps are placed the greater the wattage needed for a given illumina- tion, but this is partially offset by the greater efficiency and the wider spacing possible with larger sizes. Placing the lamps in one row midway between those in the adjacent rows will give more uni- form lighting. The space between lamps should not be more than VA times the height of the lamps above the birds; a wider spacing results in excessive light Lamp size (in watts) Lumens per watt Incandescent 15 9.5 25 10.6 40 11.7 50 13.3 60 14.0 75 15.3 100 16.4 150 18.0 200 19.0 Fluorescent (white) 72.2 69.0 48.5 48.5 makes their use unnecessary, and on whenever daylight no longer provides the desired light intensity. Thus, the poultry- man need not change the clock setting to compensate for seasonal changes in the daylength, nor does he need to turn the lights on manually on days when there is insufficient daylight. Time and photoelectric switches have a limit on the maximum wattage they can handle directly. If the wattage exceeds their limit, they should be used to operate relay switches which in turn control the lights. Table 6. Maximum Height of Lamps Above Bird Level Recommended for Different Wattage Incandescent Lamps to Obtain Given Light Intensities* Maximum height of lamps Light intensity (foot-candles) Lamp size 0.5 1.0 2.0 Reflector No reflector Reflector No reflector Reflector No reflector watts feet 15 5' 0" 6' 6" 9' 0" 14' 0" 15' 6" 19' 0" 25' 0" 3' 6" 4' 6" 6' 6" 10' 0" 10' 6" 13' 6" 17' 6" 3' 6" 4' 6" 6' 6" 10' 0" 10' 6" 13' 6" 17' 6" 2' 6" 3' 0" 4' 6" 7' 0" 7' 6" 9' 6" 12' 6" 2' 6" 3' 0" 4' 6" 7' 0" 7' 6" 9' 6" 12' 6" 1' 6" 25 2' 6" 40 3' 6" 60 5' 0" 75 5' 6" 100 7' 0" 150 . 9' 0" * Space between lamps should not be over V/2 times the height of lamp above cages. Lamps should be clean and should be operated at rated voltage. intensity directly under the lamps when suitable intensity is obtained midway be- tween lamps. Wider spacing also increases shading inside the cage by enlarging the shadow of the cage wires. Flood lamps are not often used in cage houses for this reason. Before purchasing all lamps needed, several lamps of the same wattage should be installed and the light intensity checked at various spots at bird level. This is clone with a foot-candle meter, or photometer, held horizontally so that it receives light directly from the lamps. Minimum light intensity will usually be found midway between lamps. Help in laying out the lighting system may be obtained from the University of California Agricultural Extension Serv- ice, or the electric power company serv- ing the poultry man. Electric 'Wiring All wiring materials should have the ap- proval of the Underwriters Laboratorv, and installations should conform to state and local safety regulations. (Approved materials are marked with the words Un- derwriters Laboratory or the letters UL.) Safe wiring does not necessarily guar- antee wiring adequate to prevent "volt- age drop" — that is, the reduction in voltage between the source of the electric current and the outlet where it is used. This drop is dependent on the wattage of the electrical load, size of the wire, and the distance the electricity must be con- ducted. Minimum sizes of wires to use for various distances and wattage loads in order to limit voltage drop are shown in standard wiring handbooks. The drop should not exceed 5 per cent. Future expansion or increases in the electrical load should be considered when laying out the wiring system. It is usually less expensive to wire for such expansion or increase in the initial layout than to change it later. Fig. 4: Lighting arrangement in a cage-house. If house has a shiny roof the need for reflectors is reduced. In order that the information in our publications may be more intelligible it is sometimes necessary to use trade names of products or equipment rather than complicated descriptive or chemical iden- tifications. In so doing it is unavoidable in some cases that similar products which are on the market under other trade names may not be cited. No endorsement of named products is intended nor is criticism implied of similar products which are not mentioned. Co-operative Extortion work in Agriculture an.l Home Economies College of Agriculture. University of California, and United Slates Department of Agriculture co-operating. Distribute! in furtherance of the Acts of Congress of May 8, and Jun. 30, I'M L George B. Alcorn, Dire, tor, ( lalifornia Agri. ultural Ext. nsion Service, L5m-10,'64(E7710)V.L.