EFFECT OF AGE AT STARTING BIOMITTENT LIGHTING ON PERFORMANCE OF LAYING HENS

1. Two experiments were conducted with brown-egg laying hybrid pullets to determine the optimum age at which to begin Biomittent lighting (a system providing 15 min light and 45 min darkness in each hour for 16 h). 2. In the first experiment birds introduced to Biomittent lighting at 18, 24, 30 or 36 weeks of age all gave the same egg output. Use of Biomittent lighting between 22 and 34 weeks of age reduced food intake by 5.3% compared with normal lighting during this period. 3. In the second experiment, birds introduced to Biomittent lighting at 23 or 36 weeks of age gave essentially the same egg output and this was true even for half of the flock which had been severely restricted in food intake between 6 and 18 weeks of age. 4. It is concluded that Biomittent lighting can be safely introduced at point of lay as a means of saving food consumption without loss of output provided that an adequate diet is fed. The response is interpreted as a saving in energy expenditure rather than a restriction of feeding opportunity. 5. It is recommended that, to avoid the complication of combining weekly increments in photoperiod with intermittent lighting, Biomittent lighting can be introduced abruptly as a skeleton long day. However, if this follows rearing on short photoperiods and if egg size is important, the start should be delayed until about 22 weeks of age so as not to induce early sexual maturity. © 1990, Taylor & Francis Group, LLC. All rights reserved.