Supplementary dim light differentially influences sexual maturity, oviposition time, and melatonin rhythms in pullets

Poult Sci. 2001 Dec;80(12):1723-8. doi: 10.1093/ps/80.12.1723.


The addition of two 3-h periods of very dim light, one before and one after a normal 8-h photoperiod, advances sexual maturity in pullets by about a week. This trial tested the hypothesis that dim light given before a short day of normal intensity is linked to form a more stimulatory day length and that dim light given after it is photosexually ignored. Pullets were reared from 2 d of age on 8-h photoperiods. From 10 wk, they were continued on 8-h photoperiods, transferred to 16 h, or given an 8-h period of dim light (0.09 lx) immediately before or after the main 8-h photoperiod. The bright/dim and dim/ bright groups matured at the same age, thus disproving the hypothesis tested. Both groups matured 1 wk earlier than the 8-h controls but 5 wk later than birds transferred to 16-h photoperiod. Oviposition time was similar for 8-h controls and bright/dim hens and delayed by 3 h for 16-h birds, but phase advanced by 2.4 h for dim/bright hens. Plasma melatonin rhythm was phase-advanced by about 5 h in the dim/bright hens and retarded by about 5 h in the bright/dim hens, suggesting a 13-h subjective day. However, these treatments were not regarded as fully stimulatory, as a transfer to a normal 13-h photoperiod at this age advances maturity by 5 to 6 wk. These findings show that the addition of a period of dim light to a normal nonstimulatory photoperiod differentially affects the clocks that control sexual maturation, plasma melatonin concentration, and oviposition time.

MeSH terms

  • Aging / physiology*
  • Animals
  • Antioxidants / analysis
  • Chickens / growth & development
  • Chickens / physiology*
  • Circadian Rhythm
  • Female
  • Melatonin / blood*
  • Oviposition / physiology*
  • Photoperiod
  • Random Allocation
  • Sexual Maturation / physiology*
  • Time Factors


  • Antioxidants
  • Melatonin