Response of laying hens to asymmetrical interrupted lighting regimens: physiological aspects.
1. There were no significant differences in the mean time of oviposition, distribution of ovipositions over the 24 h or proportion of eggs laid in the modal 8 h when conventionally-lit hens were compared with hens which received interrupted lighting with the same apparent daylength. 2. Intermittently-lit hens performed 25% less feeding activity than conventionally-lit hens, but without a significant reduction in mean food intake. There were genetic differences in response of feeding rate to interrupted lighting. 3. Intermittently-illuminated hens consumed about 20% of their food during the scotoperiods which interrupted the apparent day of a 1.5L:0.5D:10(0.5L:0.5D):4L:8D regimen, although there was significant genetic variation from 10 to 22%. None of the genotypes ate during the 8-h night. 4. Across 4 genotypes neither crop weight nor rate of crop emptying was affected by the lighting treatments, although a heavier mean crop weight under interrupted lighting approached significance in one breed (P less than 0.10). 5. Interrupted lighting did not cause any ocular disorders.
Lewis
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PD
Department of Animal Husbandry, University of Bristol, School of Veterinary Science, England.
Perry
G C
GC
D000818:Animals; D001947:Breeding; D002645:Chickens / Q000235:genetics / Q000502:physiology*; D003426:Crop, Avian / Q000502:physiology; D004435:Eating; D005123:Eye / Q000033:anatomy & histology; D005247:Feeding Behavior; D005260:Female; D005838:Genotype; D008027:Light; D010058:Oviposition; D010507:Periodicity