Therefore feed intake gets considerably reduced at dark (Perry, 1981). Gradual decreasing photoperiods during growth delays sexual maturity. However similar photoperiods have been shown to increases body and egg weight (Keshavarz, 1998) of pullets. The most prominent role of light has been recognized in the regulation of dark hormone melatonin. Photoperiod regulates melatonin secretion from pineal gland (Brennan et al., 2002) which affects thermoregulation, reproduction and behaviour of birds (Apeldoorn et al., 1999).

Photoperiod

There are several reported advantages and disadvantages of different light treatment. Longer photoperiod is reported to improve yield and FCR (Beane et al., 1979; Ozcan and Akcapinar, 1993) but affect the eye (Li et al., 1995; Prescott et al., 2003), increases leg problems (Sanotra et al., 2002), body asymmetry (Moller et al., 1999; Campo et al., 2007), stress and health issues of birds (Moller et al., 1999). Similarly shorter photoperiod reduces feed intake, growth (Lewis et al., 1998) and breast meat yield (Lien et al., 2008). Heterophil-to-lymphocyte ratio is an indicator of stress condition in chicken (Onbasilar et al., 2007; Fathi et al., 2008). However available reports indicate that effect of light on H/L ratio is contradictory. Campo and Da´vila (2002) did not notice any effect of continuous light on H/L ratio whereas Moore and Siopes (2000), Campo et al., (2007) and Zulkifli et al., (1998) found a significant difference in continuous light as compared to other light schedules. The stress hormone, plasma corticosterone level was found to be low in intermittent photoperiods indicating less stress in broilers (Olanrewaju et al., 2006). Further, the changing light dark cycles not only reduces fear in broilers (Campo and Da´vila, 2002; Sanotra et al., 2002) but it was also found to improve growth and health (Milosevic et al., 1999) of the birds as compared to continuous or near continuous (23L: 1D) light schedule. Initial reduction followed by increasing photoperiods reduces ascites (Lott et al., 1996), sudden death syndrome (Blair et al., 1993) and leg disorders (Classen et al., 1991; Riddell and Classen, 1992) in broilers. A longer exposer of birds to light or darkness seems to have adverse effects in birds. Long period of light and darkness is reported to have negative effect on growth and feed efficiency (Deaton et al., 1976). Long period of darkness is not beneficial as feed intake gets considerably reduced resulting in fasting, hunger, frustration (De Jongs et al., 2002), nutritional stress (Ketchik and Sykes, 1978) and eye abnormality (Oishi and Mirakami, 1985) in broilers.

Light schedule 16L:8D was found beneficial as it reduces physiological stress (Gordon, 1994), leg problems, chronic fear (Sanotra et al., 2002) and positive welfare including improved immunity, increased sleep and leg health in birds (Classen et al., 2004b). At the maturity age of the bird increase of light duration beyond 16 hours did not show any significant effect. Body weight of broilers exposed to photoperiods between 20L:4D and 16L:8D was similar to those provided with 23L:1D at the maturity age of birds (Renden et al., 1996; Laster et al., 1999). On the other hand, photoperiod lesser than 14L:10D decrease body weight as compared to continuous lighting (Ingram et al., 2000). Increasing photoperiod with increase in age of bird enhance the rate of fat deposition, reduces breast meat (Boon et al., 2000; Downs et al., 2006), increases testis size (Follett and Maung, 1978), decreases mortality rate (Charles et al., 1992; Renden et al., 1993) with less incidence of leg abnormalities (Classen et al., 1994). It also increases feed consumption in young birds as compared to birds exposed to other light schedules (Lott et al., 1996). However, there are contradictory results of others stating that photoperiods have no effect on growth (Archer et al., 2009), FCR (Onbasilar et al., 2007), fat deposition (Onbasilar et al., 2007) and breast muscle (Chen et al., 2007) of birds at maturity age.

Intermittent lighting has gained considerable importance during last few years. It not only saves electricity and reduces cost of production (Lien et al., 2007) but also significantly improves growth and feed efficiency in birds (Ohtani and Leeson, 2000; Rahimi et al., 2005; Canan and Emsen, 2006). There are also reports of reduced leg disorder (Petek et al., 2005), ascites (Albers and Frankenhuis, 1990) and abdominal fat deposition (Rahimi et al., 2005) in birds reared under intermittent light schedule. Nys and Mongin (1980), Skoglund and Whittaker (1980) and Sauveur and Mongin (1983) reported increased egg weight in brids whereas Buyse et al., (1996) reported increased protein content in broilers reared under intermittent light treatment.There are reports of temporary delayed growth rate in birds shifted from continuous lighting to intermittent lighting which later gets compensated at maturity age (Ohtani and Tanaka, 1997). Ohtani and Tanaka (1998) observed that broilers were more excited while feeding in intermittent lighting as compared to continuous light schedule. Male birds are reported to benefit more as compared to females regarding their body weight gain (Charles et al., 1992). However, increased fat deposition in IL schedule was observed by Ohtani and Leeson (2000) and reduced FCR by Onbasilar et al., (2007). In other studies no difference was observed between intermittent and continuous light treatment on growth performance of birds (Onbasilar et al., 2007).

Light treatment affects hatchability of the birds (Shafey et al., 2005). Further it is reported that hatchability varies as a function of light wavelength. Green, blue and UV light favours hatching (Shafey and Al-Mohsen, 2002), skeletal development (Zhang et al., 2006), post hatch growth effects (Rozenboim et al., 2003; Rozenboim et al., 2004) and fertility (Lewis and Gous, 2009) in poultry birds. Layers incubated at dark showed difference in pecking behaviour during the rearing period (Riedstra and Groothuis, 2004). High light intensities during incubation may contribute improper development of nervous system (Rogers, 1982) resulting in increased aggressiveness among birds (Rogers and Workman, 1989). Incubation in pink light decreases chick weight after hatch (Tamimie, 1967). Utilization of compact fluorescent light is more beneficial in poultry industry as it promotes poultry growth and saves electricity (Darre and Spandorf, 1985; Scheideler, 1990). Fluorescent light has positive effect on vision (Prescott and Wathes, 1999) and physical activity (Boshouwers and Nicaise, 1993) of birds. Birds reared in either incandescent light or fluorescent light did not show any difference in growth rate and FCR (Scheideler, 1990).

Light intensity

Light intensity (measured in lux or foot candle) has its importance in poultry farming (Kristensen et al., 2006). It is measured as average of three planes at right angle to each other using a lux meter (Prescott et al., 2003). Terms such as “clux” (chicken-lux), “galluiminance” or “turkey-lux” is the illuminance adjusted to photosensivity curve of fowl (Prescott and Wathes, 1999). Various studies on performance of light intensity in poultry production have been conducted (Boshouwers and Nicaise, 1987; Yahav et al., 2000; Lien et al., 2007; Blatchford et al., 2009). Higher light intensities in near continuous light period have negative effects on health (Bessei, 2005), increases eye problem (Oishi and Mirakami, 1985) increase mortality and induces aggressive pecking behaviour (Moinard et al., 2001) in birds. However this light treatment may be beneficial for the birds on other aspects. It was found that higher light intensities increases physical activity (Newberry et al., 1988) and reduces leg abnormality (Classen et al., 1991). Improvement in communication (Manning and Stamp, 1998) and reduced pecking behaviour (Sherwin et al., 1999) among birds reared under UV light are reported. However, high intensity UV light develops conjunctivitis in birds (Barott and Pringle 1951). Available literature suggests that the effect of high light intensity on birds is inconsistent. Increase in mortality rate has been reported in several studies (Suh et al., 1998). In other studies it did not show any effect on mortality rate (Lien et al., 2007; Lien et al., 2008). Similarly it has also been reported that stress level is unaffected as a function of increase in light intensity (Lien et al., 2007).

Low light intensity increases feed conversion and promotes higher body mass in birds (Kristensen et al., 2006; Blatchford et al., 2009). It also reduces abdominal fat (Charles et al., 1992) and fear (Gregory et al., 1993). Detrimental effects of low light intensity such as decreased breast meat yield (Downs et al., 2006; Lien et al., 2007), feed intake (Prescott and Wathes, 2002) and reduced physical activity (Blatchford et al., 2009) have been reported. Low intensity light also increases eye problems (Buyse et al., 1996) and compromises welfare among birds (Blatchford et al., 2009). Classen et al., (1991) reported higher mortality rates in birds reared under low light intensity which was contradicted by the finding of Newberry et al., (1988), Charles et al., (1992), Lien et al., (2007) and Lien et al., (2008) who reported that low light intensity has no effect on mortality of birds.

On the contrast, Charles et al., (1992) have reported no effect of light on sexual maturity. Various light intensities such as 0 lux (Malleau et al., 2007), 0.5 lux (Berk 1997), 1-4 lux (Coenen et al., 1988), less than 0.25 lux of blue light (March et al., 1990) and 3 lux of blue light (Van Luijtelaar et al., 1987) have been recommended for dark phase to optimise productivity. Higher feed consumption was found in 3.2 lux (Wathes et al., 1982) and 2.7 lux (Downs et al., 2006). Light intensites between 5 to 51 lux (Buyse et al., 1996), 1.75 to 162 lux (Lien et al., 2008), 0.5 to 32.5 lux (Newberry et al., 1986), 4 to 20 lux (Scheideler, 1990), 5 to 150 lux (Charles et al., 1992) and 5 to 100 lux (Kristensen et al., 2006) were reported to have no effect on feed consumption. Interestingly a great variation in the predilection of birds towards light intensity as a function of age ranging from 6 to 200 lux has been reported (Berk, 1997; Davis et al., 1999). Light intensity of 20 lux is recommended as ideal for growing birds (Manser, 1996). Further it has been reported that less than 100 lux light is not suitable for proper vision in birds (Kristensen et al., 2002). Turkeys develop eye abnormality at intensities between 1.1 and 11 lux (Siopes et al., 1983; Siopes et al., 1984).

There are numerous literature which states that light intensity has no effect on feed conversion (Downs et al., 2006; Lien et al., 2008), feed uptake (Kristensen et al., 2006; Downs et al., 2006), body weight (Kristensen et al., 2006), abdominal fat (Downs et al., 2006) and mortality (Lien et al., 2007; Lien et al., 2008). However, decreasing light intensity improves FCR (Cherry and Barwick, 1962) and reduces physical activity (Downs et al., 2006) in birds.

Monochromatic light

Light colour also affects physiological parameters in birds. Green light and blue light stimulates growth in birds (Rozenboim et al., 2004; Cao et al., 2008) as compared to red or white light (Woodward et al., 1969). However, red and white light as compared to blue light have been reported to augment body mass in turkeys (Leighton and Mason, 1976). Further, red light also reduces cannibalism (Bowlby, 1957; Schumaier et al., 1968). Intermittent green light during incubation increases body weight at maturity age (Rozenboim et al., 2003; Rozenboim et al., 2004). High intensity red light improves leg condition (Prayitno et al., 1997) in female broilers. Blue and green light stimulates growth while orange and red light stimulates reproduction (Waybeck and Skoglund, 1974). However Harrison et al., (1969) stated that hens mature late in red light but rate of egg lay increased when blue or green light treated birds were place in red light. Wabeck and Skoglund (1974) also observed increased growth and FCR in broilers exposed to green and blue light. El-Husseiny et al., (2000) reported green light to significantly affect growth whereas red and white light slightly increased egg production and feed utilization energy in layers. Chicks preferred red light followed by yellow light environment during rearing (Taylor et al., 1969). Broilers are easy to catch at dim blue light as they show less fear (Bowlby, 1957). Gregory et al., (1993) reported that at 12 lux birds are more fearful and causes wing flapping than at lower intensity.

It can be concluded that light plays an important role in poultry industry, as optimum lighting condition not only increases production efficiency but also take care the welfare issues of the poultry birds. In the present industrial scenario, available literature suggest that continuous lighting is not beneficial as it causes metabolic disorders, eye problem and leg abnormality among birds. In addition, electric consumption is also higher in the continuous lighting regiment. Thus intermittent lighting schedule seems to be more suitable because it not only saves electric consumption, but also results in similar weight gain as compared to continuous lighting.

BIBLIOGRAPHY:

1. Albers G. and Frankenhuis M. (1990). Ascites, a high altitude disease in the lowlands. Poultry, 6(1): 24-25.

2. Al–Homidan A.A. and Petchey A.M. (2001). The effects of length and color of light regimes on performance and carcass characteristics of broiler chickens. Egypt. Poult. Sci., 21(II):549-566.

3. Apeldoorn E.J., Schrama J.W., Mashaly M.M. and Parmentier H.K. (1999). Effect of melatonin and lighting schedule on energy metabolism in broiler chickens. Poult. Sci., 78: 223-229.

4. Appleby M.C., Mench J.A. and Hughes B.O. (2004). Poultry Behaviour and Welfare. (Wallingford, U.K.: CABI Publishing).

5. Archer G.S., Shivaprasad H.L. and Mench J.A. (2009). Effect of providing light during incubation on the health, productivity and behavior of broiler chickens. Poultry Science, 88: 29-37.

6. Barott H.G. and Pringle K.M. (1951). Effect of environment on growth and feed and water consumption in chickens. IV. The effect of light on early growth. The Journal of Nutrition, 45: 265-274.

7. Beane W.L., Cherry J.A. and Weaver Jr. W.D. (1979). Intermittent light and restricted feeding of broiler chickens. Poultry Sci., 58(3): 567-571.

8. Berk J. (1997). Influence of light intensity on light choice of broilers. 5th European Symposium on PoultryWelfare, Wageningen. 46-48

9. Bessei W. (2005). Welfare of meat producing poultry—an overview. Anim. Sci. Pap. Rep., 23(1): 205-216.

10. Bessei W. (2006). Welfare of broilers: a review. World’s Poultry Science Journal, 62: 455-466

11. Blair R., Newberry R.C. and Gardiner E.E. (1993). Effects of lighting pattern broiler house lighting source and photoperiod. Poult. Sci., 69: 1471-1479.

12. Blatchford R.A., Klasing K.C., Shivaprasad H.L., Wakenell P.S., Archer G.S. and Mench J.A. (2009). The effect of light intensity on the behavior, eye, leg health, and immune function of broiler chickens. Poult. Sci., 88: 20-28.

13. Blockhuis H.J. (1983). The relevance of sleep in poultry. World’s Poultry Science Journal, 39(1): 33-37.

14. Boon P., Visser G.H. and Daan S. (2000). Effect of photoperiod on body weight gain, and daily energy intake and energy expenditure in Japanese quail (Coturnix c.Japonica). Physiology and Behaviour, 70: 249-260.

15. Boon P., Watt P.W., Smith K. and Visser G.H. (2001). Day length has a major effect on the response of protein synthesis rates to feeding in growing Japanese quail. Journal of Nutrition, 131(2): 268-275.

16. Boshouwers F.M. and Nicaise E. (1987). Physical activity and energy expenditure of laying hens as affected by energy light intensity. Br. Poult. Sci., 28(1): 155-163.

17. Boshouwers F.M. and Nicaise E. (1993). Artificial light sources and their influence on physical activity and energy expenditure of laying hens. Br. Poult. Sci., 34(1): 11-19.

18. Bowlby G.M.S. (1957). Some preliminary investigations into the effect of light on broilers. World’s Poult. Sci. J., 13(3): 214-226.

19. Brennan C.P., Hendricks G.L., El-Sheikh T.M. and Mashaly M.M. (2002). Melatonin and the enhancement of immune responses in immature male chickens. Poult. Sci., 81(3): 371-375.

20. Buyse J., Kuhn E.R. and Decuypere E. (1996). The use of intermittent lighting for broiler production. 1. Effect on male and female broiler performance, and on efficiency of dietary nitrogen retention. Poultry Sci., 75: 589-594.

21. Campo J.L. and Davila S.G. (2002). Effect of photoperiod on heterophil to lymphocyte ratio and tonic immobility duration of chickens. Poult. Sci., 81: 1637-1639.

22. Campo J.L., Gil M.G., Dávila S.G. and Muñoz I. (2007). Effect of lighting stress on fluctuating asymmetry heterophil-tolymphocyte ratio, and tonic immobility duration in eleven breeds of chickens. Poult. Sci., 86(1): 37-45.

23. Canan B.S. and Emsen H. (2006). The effect of diet with low protein and intermittent lighting on ascites induced by cold temperatures and growth performance in broilers. International Journal of Poultry Science, 5(10): 988-991.

24. Cao J., Liu W., Wang Z., Xie D. and Chen Y. (2008). Green and blue monochromatic lights promote growth and development of broilers via stimulating testosterone secretion and microfiber growth. J. Appl. Poult. Res., 17: 211-218.

25. Charles R.G., Robinson F.E., Hardin R.T., Yu M.W., Feddes J. and Classen H.L. (1992). Growth, body composition and plasma androgen concentration of male broiler chickens subjected to different regimens of photoperiod and light intensity. Poult. Sci., 71(10): 1595-1605.

26. Chen H., Huang R.L., Zhang H.X., Di K.Q., Pan D. and Hou Y.G. (2007). Effect of photoperiod on ovarian morphology and carcass traits at sexual maturity in pullets. Poult. Sci., 86(5): 917-920.

27. Cherry P. and Barwick M.W. (1962). The effect of light on broiler growth. I. Light intensity and colour. Brit. Poult. Sci., 3(1): 31-39.

28. Classen H.L., Annett C.B., Schwean-Lardner K.V., Gonda R. and Derow D. (2004b). The effects of lighting programmes with twelve hours of darkness per day provided in one, six or twelve hour intervals on the productivity and health of broiler chickens. Br. Poult. Sci., 45(1): S31-32.

29. Classen H.L., Riddell C. and Robison F.E. (1991). Effect of increasing photoperiod length on performance and health of broiler chickens. British Poultry Science, 32(1): 21-29.

30. Classen H.L., Riddell C., Robinson F.E., Shand P.J. and McCurdy A.R. (1994). Effect of lighting treatment on the productivity, health, behaviour and sexual maturity of heavy male turkeys. British Poultry Science, 35(2): 215-225.

31. Coenen A.M.L., Wolters E.M.T.J., Van Luijtelaar E.L.J.M. and Blokhuis H.J. (1988). Effects of intermittent lighting on sleep and activity in the domestic hen. Applied Animal Behaviour Science, 20(3): 309-318.

32. Cuthill I.C., Partridge J.C., Bennett A.T.D., Church S.C., Hart N.S. and Hunt S. (2000). Ultraviolet vision in birds. Adv. Stud. Behav.,29: 159-214.

33. Darre M.J. and Spandorf A.H. (1985). Energy efficient cost effective lights for use with poultry. Poultry Sci., 64: 85.

34. Davis N.J., Prescott N.B., Savory C.J. and Wathes C.M. (1999). Preferences of growing fowls for different light intensities in relation to age, strain and behaviour. Anim. Welfare, 8(3): 193-203.

35. de Jongs l.C., van Voorst S., Ehlhardt D.A. and Blokhuis H.J. (2002). Effects of restricted feeding on Physiological stress parameters in growing broiler breeders. Br. Poult. Sci., 43(2): 157-168.

36. Deaton J.W., Reece F.N., Kubena L.F. and May J.D. (1976). Effect of varying light intensity on broiler performance. Poultry Sci., 55(2): 515-519.

37. Downs K.M., Lien R.J., Hess J.B., Bilgili S.F. and Dozier W.A. (2006). The effects of photoperiod length, light intensity and feed energy on growth responses and meat yield of broilers. J. Appl. Poult. Res., 15(3): 406-416.

38. El-Husseiny O., Hashish S.M., Arafa S.A. and Madian A.H.H. (2000). Response of poultry performance to environmental light colour. Egyptian Poultry Science Journal,20(2): 385-402.

39. Fathi M.M., El-Attar A.H., Ali U.M. and Nazmi A. (2008). Effect of the neck neck gene on carcass composition and immune competence in chicken. Br. Poult. Sci., 49: 103-110.

40. Follett B.K. and Maung S.L. (1978). Rate of testicular maturation in relation to gonadotrophin and testosterone levels in quail exposed to various artificial photoperiods and to natural daylengths. Journal of Endocrinology, 78(2): 267-280.

41. Gordon S.H. (1994). Effect of Daylength and İncreasing Daylength Programmes on Broiler Welfare and Performance. World’s Poultry Science Journal, 50: 269-281.

42. Gregory N.G., Wilkins L.J., Alvey D.M. and Tucker S.A. (1993). Effect of catching method and lighting intensity on the prevalence of broken bones and on the ease of handling of end-of-lay hens. Veterinary Record, 132(6): 127-129.

43. Harrison P., McGinnis J., Schumaier G. and Lauber J. (1969). Sexual maturity and subsequent reproductive performance of White Leghorn chickens subjected to different parts of the light spectrum. Poultry Sci., 48(3): 878-883.

44. Hart N.S. (2001). The visual ecology of avian photoreceptors. Prog. Retin. Eye Res.,20(5): 675-703.

45. Honkavaara J., Koivula M., Korpimaki E., Siitari H. and Viitala J. (2002). Ultraviolet vision and foraging in terrestrial vertebrates. Oikos, 98: 505-511.

46. Houser J. and Huber-Eicher B. (2004). Do domestic hens discriminate between familiar and unfamiliar conspecifics in the absence of visual cues? Applied Animal Behaviour Science, 85: 65-76.

47. Ingram D.R. and Hatten L.F. (2000). Effects of light restriction on broiler performance and specific body weight structure measurements. J. App. Poult. Res., 9: 501-504.

48. Keshavarz K. (1998). Effect of light regimen, floor space and energy and protein levels during the growing period on body weight and early egg size. Poult. Sci., 77(9): 1266-1279.

49. Ketchik I.T. and Sykes A.H. (1978). Effect of complete starvation on plasma and tissue ascorbic acid concentration. Malaysian Applied Biol., 7: 81.

50. Kliger C.A., Gehad A.E., Hulet R.M., Roush W.B., Lillehoj H.S. and Mashaly M.M. (2000). Effects of photoperiod and melatonin on lymphocyte activities in male broiler chickens. Poultry Science,79(1): 18-25.

51. Kristensen H.H., Perry G.C., Prescott N.B., Ladewig J., Ersboll A.K. and Wathes C.M. (2006). Leg health and performance of broiler chickens reared in different light environments. Br. Poult. Sci., 47(3): 257-263.

52. Kristensen H.H., Prescott N.B., Ladewig J., Perry G. and Wathes C.M. (2002). Light quality and the visual acuity in broiler chickens. Proceedings of the 36^thInternational Congress of the ISAE, Egmond aan Zee, The Netherlands.

53. Laster C.P., Hoerr F.J., Bilgili S.F. and Kincaid S.A. (1999). Effects of dietary roxarsone supplementation, lighting program and season on the incidence of leg abnormalities in broiler chickens. Poult. Sci., 78(2): 197-203.

54. Leighton A.T. and Mason J.P. (1976). Environmental factors affecting growth performance of turkeys. Am. Soc. Agric. Eng., 76: 4508.

55. Lewis P.D. and Gous R.M. (2009). Responses of poultry to ultraviolet radiation. World’s Poult. Sci. J., 65(3): 499-510.

56. Lewis P.D., Perry G.C. and Sherwin C.M. (1998). Effect of photoperiod and light intensity on the performance of intact male turkeys. Animal Science, 66(03): 759-767.

57. Li T., Troilo D., Glasser A. and Howland H. (1995). Constant light produces severe corneal flattening and hyperopia in chickens. Vision Res., 35(9): 1203-1209.

58. Lien R.J., Hess J.B., McKee S.R. and Bilgili S.F. (2008). Effect of light intensity on live performance and processing characteristics of broilers. Poult. Sci., 87(5): 853-857.

59. Lien R.J., Hess J.B., McKee S.R., Bilgili S.F. and Townsend J.C. (2007). Effect of light intensity and photoperiod on live performance, heterophil to lymphocyte ratio and processing yields of broilers. Poult. Sci., 86(7): 1287-1293.

60. Lott B.D., Branton S.L. and May J.D. (1996). The effect of photoperiod and nutrition on ascites incidence in broilers. Avian Dis., 40(4): 788-791.

61. Malleau A.E., Duncan I.J.H., Widowski T.M. and Atkinson J.L. (2007). The importance of rest in young domestic fowl. Applied Animal Behaviour Science, 106(1): 52-69.

62. Manning A. and Stamp D.M. (1998). An Introduction to Animal Behaviour (5th Edition). Cambridge: Cambridge University Press.

63. Manser C.E. (1996). Effects of lighting on the welfare of domestic poultry: A review. Anim. Welfare, 5(4): 341-360.

64. March T.J., Thompson L.J., Lewis P.D. and Perry G.C. (1990). Sleep and activity behaviour of layers subjected to interrupted lighting schedules. British Poultry Science, 31: 895-896.

65. Milosevic N., Peric L., Supic B. and Pavloviski Z. (1999). Body mass and dynamics of growth of broiler chickens of different genotypes reared under intermittent light programme. Zivinarstvo, 5: 30-39.

66. Moinard C., Lewis P.D., Perry G.C. and Sherwin C.M. (2001). The effects of light intensity and light source on injuries due to pecking of male domestic turkeys (Meleagris gallopavo). Anim. Welfare,10(2): 131-139.

67. Moller A.P., Sanotra G.S. and Vestergaard K.S. (1999). Developmental instability and light regime in chickens (Gallus gallus). Appl. Anim. Behav. Sci., 62(1): 57-71.

68. Newberry R.C., Hunt J.R. and Gardiner E.E. (1988). Influence of light intensity on behavior and performance of broiler chickens. Poult. Sci., 67(7): 1020-1025.

69. Nys Y. and Mongin P. (1980). Jejunal calcium permeability in laying hens during egg formation. Reprod. Nutr. Develop., 20(1A): 155-161.

70. Ohtani S. and Leeson S. (2000). The effect of intermittent lighting on metabolizable energy intake and heat production of male broilers. Poult. Sci.,79(2): 167-171.

71. Ohtani S. and Tanaka K. (1997). The effects of intermittent lighting pattern of light-dark ratio, one to two, on performance and meat quality in male broiler chickens. Jpn. Poult. Sci.,34(6): 382-387.

72. Ohtani S. and Tanaka K. (1998). The effects of intermittent lighting on activity of broiler chickens. Jpn. Poult. Sci., 35(2): 117-124.

73. Oishi T. and Murakami N. (1985). Effects of duration and intensity of illumination on several parameters of the chick eye. Comp. Biochem. Physiol. A Comp. Physiol., 81(2): 319-23.

74. Olanrewaju H.A., Thaxton J.P., Dozier W.A., Purswell J., Roush W.B. and Branton S.L. (2006). A Review of Lighting Programs for Broiler Production. Inr. J. of Poultry Science,5(4): 301-308.

75. Onbasilar E.E., Erol H., Cantekin Z. and Kaya Ü. (2007). Influence of intermittent lighting on broiler performance, incidence of tibial dyschondroplasia, tonic immobility, some blood parameters and antibody production. Asian-Aust. J. of Animal Sci., 20(4): 550-555.

76. Ozcan I. and Akcapinar H. (1993). Effect of different lighting programs on growth and carcass quality in quails. Lalahan Hay. Ars. Ens., 33(1-2): 65-84.

77. Perry G.C. (1981). Growth and food intake of broilers under various lighting regime. Br. Poult. Sci.,22(3): 219-225.

78. Petek M., Sönmez G.,Yildiz H. and Baspinar H. (2005). Effects of different management factors on broiler performance and incidence of tibial dyschondroplasia. Br. Poult. Sci., 46(1): 16-21.

79. Prayitno D.S., Phillips C.J. and Omed H. (1997). The effects of color of lighting on the behaviour and production of meat chickens. Poult. Sci., 76(3): 452-457.

80. Prescott N.B. and Wathes C.M. (1999). Spectral sensitivity of the domestic fowl (Gallus g. domesticus). British Poultry Science, 40(3): 332-339.

81. Prescott N.B. and Wathes C.M. (2002). Preferences and motivation of laying hens to eat under different illuminances and the effect of illuminance on eating behaviour. British Poultry Science, 43(2): 190-195.

82. Prescott N.B., Wathes C.M. and Jarvis J.R. (2003). Light, vision and the welfare of poultry. Animal Welfare, 12(2): 269-288.

83. Rahimi G., Rezaei M., Haffzian H. and Saiyahzadeh H. (2005). The effect of intermittent lighting schedule on broiler performance. Int. J. Poult. Sci., 4(6): 396-398.

84. Renden J.A., Bilgili S.F. and Kincaid S.A. (1993). Comparison of restricted and increasing light programs for male broiler performance and carcass yield. Poult. Sci., 72(2): 378-382.

85. Renden J.A., Moran E.T. and Kincaid S.A. (1996). Lighting programs for broilers that reduce leg problems without loss of performance or yield. Poult. Sci., 75(11): 1345-1350.

86. Riddell C. and Classen H.L. (1992). Effects of increasing photoperiod length and anticoccidials on performance and health of roaster chickens. Avian Dis., 36(3): 491-498.

87. Riedstra B. and Groothuis T.G.G. (2004). Prenatal light exposure affects early feather-pecking behaviour in the domestic chick. Animal Behaviour, 67(6): 1037-1042.

88. Rogers L.J. (1982). Light experience and asymmetry of brain-function in chickens. Nature, 297(5863): 223-225.

89. Rogers L.J. and Workman L. (1989). Light exposure during incubation affects competitive behaviour in domestic chicks. Appl. Anim. Behav. Sci., 23(3): 187-198.

90. Rozenboim I., Biran I., Chaiseha Y., Yahav S., Rosenstrauch A., Sklan D. and Halevy O. (2004). The effect of green and blue monochromatic light combination on broiler growth and development. Poult. Sci., 83(5): 842-845.

91. Rozenboim I., Huisinga R., Halevy O. and El Halawani M.E. (2003).Effect of embryonic photo stimulation on the post hatch growth of turkey poults. Poult. Sci.,82(7): 1181-1187,

92. Sanotra C.S., Lund D.J. and Vestergaard K.S. (2002). Influence of Light-Dark schedules and stocking density on behaviour, risk of leg problems and occurrence of chronic fear in broilers. British Poultry Science,43(3): 344-354.

93. Sauveur B. and Mongin P. (1983). Performance oflayers reared and/or kept under different 6-hour light-dark cycles. Br. Poult Sci., 24(3):405-416.

94. Scheideler S.E. (1990). Research Note: Effect of various light sources on broiler performance and Efficiency of Production under Commercial Conditions. Poult. Sci., 69(6): 1030-1033.

95. Schumaier G., Harrison P.C. and McGinnis J. (1968). Effects of colour fluorescent light on growth, cannibalism and subsequent egg production of single comb White Leghorn pullets. Poultry Sci., 47(5): 1599-1602.

96. Shafey T.M. and Al-Mohsen T.H. (2002). Embryonic growth, hatching time and hatchability performance of meat breeder eggs incubated under continuous green light. Asian-australas. J. Anim. Sci., 15(12): 1702-1707.

97. Shafey T.M., Al-Batshan H.A., Ghannam M.M. and Al-Ayed M.S. (2005). Effect of Intensity of Egg Shell Pigment and Illuminated Incubation on Hatchability of Brown Eggs. British Poultry Science, 46(2): 190-198.

98. Shariatmadari F. and Moghadamian A.A. (2007). Effect of early feed restriction in combination with intermittent lighting during the natural scotoperiod on performance of broiler chicken. J. Sci. & Technol. Agric. and Natur. Resour.,11(40): 363-374

99. Sherwin C.M., Lewis P.D. and Perry G.C. (1999). Effects of environmental enrichment, fluorescent and intermittent lighting on injurious pecking amongst male turkey poults. British Poultry Science, 40(5): 592-598.

100. Siopes T.D., Timmons M.B., Baughman G.R. and Parkhurst C.R. (1984). The effects of light intensity on turkey poult performance eye morphology and adrenal weight. Poultry Science, 63(5): 904-909.

101. Siopes T.D., Timmons M.B., Baughman G.S. and Parkhurst C.R. (1983). The effect of light-intensity on the turkey poult eye morphology. Poultry Science, 62(12): 2486-2488.

102. Skoglund W.C. and Whittaker D. (1980). Interrupted lighting programs for brown egg breeds. Poultry Sci., 59(11): 2397-2399.

103. Suh O.S., Choi H.C.,Lee D.S.,Lee S.J.,Jang B.G.,Han J.D. and Park Y.Y. (1998). Effects of lighting programes on the performance and SDS incidence of broiler chicks. J. Liv. St. Sci., 40(1): 81-87.

104. Tamimie H.S. (1967). Light exposure of incubating eggs and its influence of the growth of chicks. I. Brooding chicks under different light regimens. Comp. Biochem. Physiol., 21(1): 59-63.

105. Taylor A., Sluckin W. and Hewitt R. (1969). Changing colour preferences of chicks. Anim. Behav., 17(1): 3-8.

106. Van Luijtelaar E.L., Van Der Grinten C.P., Blokhuis H.J. and Coenen A.M. (1987). Sleep in the domestic hen (Gallus domesticus). Physiology and Behaviour, 41(5): 409-414.

107. Wathes C.M., Spechter H.H. and Bray T.S. (1982). The effects of light illuminance and wavelength on the growth of broiler chickens. J. Agric. Sci., 98(1): 195-201.

108. Waybeck C.J. and Skoglund W.C. (1974). Influence of radiant energy from fluorescent light sources on growth, mortality and feed conversion of broilers. Poult Sci., 53(6): 2055-2059.

109. Woodward A.E., Moore J.A. and Wilson W.O. (1969). Effect of wavelength of light on growth and reproduction in Japanese quail (Coturnix coturnix japonica). Poultry Sci., 48(1): 118-123.

110. Yahav S., Hurwitz S. and Rozenboim I. (2000). The effect of light intensity on growth and development of turkey toms. Br. Poult. Sci., 41(1): 101-106.

111. Yano J., Oshima S. and Gotoh J. (1974). Effects of various lighting regimes on diurnal rhythms of EEG components in the chicken. Poultry Science, 53(3): 918-923.

112. Zhang L., Zheng-xiang S., Xin-ying W., Ai-lian G. and Bao-ming L. (2006). Effects of ultraviolet radiation on skeleton development of broiler chickens. Agri. Sci. in China, 5(4): 313-317.

113. Zulkifli I., Rasedee A., Nor Syaadoh O. and Che Norma M.T. (1998). Day length effects on stress and fear responses in broiler chickens. Asian-Aust. J. Anim. Sci., 11(6): 751-754.

Received on 25.05.2012

Modified on 13.06.2012

Accepted on 12.08.2012

Research J. Science and Tech. 4(4): July-August. 2012: 172-177