Effect of monochromatic light on sexual maturity, production performance and egg quality of laying hens

A study was conducted to evaluate the effect of monochromatic light on sexual maturity, production performance, and egg quality of laying hens. A total of 144 14-week-old Hy-Line Brown chickens were reared in cages and illuminated under four different light treatment groups with three replicates (12 birds per replication, n = 12) for 14 to 60 weeks. A 60 W incandescent light bulb (IL) was used as a control, and white light (WL), blue light (BL), and red light (RL) were produced using light emitting diode lamps. The four light treatment groups each had an intensity of 20 lux. A significant delay in laying was observed when pullets were reared under BL compared to all the other light treatments. By contrast, pullets reared under RL laid significantly earlier than those under IL and BL. Hens reared under RL produced significantly higher number of eggs than those under IL and BL, and hens reared under WL produced more eggs than those under BL from 18 to 60 weeks. Feed intake was significantly increased when birds were reared under RL compared to WL and BL. The egg weight was significantly higher in BL compared to WL and RL from 41 to 50 weeks. The FCR was significantly increased when birds were reared under RL compared to other light treatments from 31 to 40 weeks and from 18 to 60 weeks. By contrast, birds reared under RL exhibited significantly increased egg shell thickness compared to birds reared under IL and BL. The ovary weight of laying pullets grown under WL was significantly higher compared to other treatments at 16 weeks of age. It is concluded that birds reared under RL matured earlier, increased egg production and egg shell thickness, but feed conversion rate was not improved under RL.