| Continuous: 16L:8D, 14L:10D, 12L:12D | Beijing You Chicken (week 56—64) | Continuous lighting → ↑ ovarian weight, oviduct weight/length, and follicle numberLighting → altered circadian behaviors (feeding, laying, sleeping) No effect on laying performance | Geng et al. (2022b) |
| Intermittent: 12L:2D:4L:6D, 10L:2D:4L:8D, 8L:4D:4L:8D |
| Continuous: 16L:8D, 12L:12D | Beijing You Chicken (week 19—34) | Intermittent (12L:2D:4L:6D) → ↑ pineal Opn4 expressionContinuous (12L:12D) → ↓ Opn4 expressionIntermittent lighting → negative correlation between Opn4 and melatoninLighting → influenced circadian behaviors No effect on laying performance | Geng et al. (2022a) |
| Intermittent: 12L:2D:4L:6D |
| Continuous: 16L:8D | ISA hens (week 56—64) | 9L:15D → ↑ shell hardness, Ca & P deposition9L:15D → ↑ serum Ca & P during dark phase9L:15D → ↓ feed intake, ↓ egg weightNo effect on laying performance | Xin et al. (2021) |
| Long dark phase: 9L:15D |
| Continuous: 16L:8D | Rhode Island Red (week 20—36) | Shorter light pulses (20 m) → ↑ laying rate, ↑ egg mass, ↑ shell thickness → ↑ antioxidant capacity, ↓ oxidative stressNo effect on feed intake, BW, egg weight, Haugh unit, or yolk index | Farghly et al. (2019) |
| Intermittent: 20 min/h light pulses + 40 min/h dark, 40 min/h light pulses + 20 min/h dark |