Light intensity effects on performance, activity, leg disorders, and sudden death syndrome of roaster chickens

The effects of light intensity on performance, activity, leg disorders and sudden death syndrome (SDS) of male chickens were examined in two experiments. In each experiment 5,600 1-day-old chicks were divided evenly between 8 light-proof floor pens and reared to 9 weeks of age on one of four light intensity treatments: .5, 10, 20, and 30 1x in Experiment 1 and .1, 1, 10, and 100 1x in Experiment 2. Light intensities less than 10 1x were phased in gradually by 3 weeks of age. Light intensity had no effect on 3, 6, or 9-week body weight, incidence of leg disorders, total mortality, or mortality due to SDS in either experiment (P greater than .05). Effects of light intensity on feed conversion and carcass quality were inconsistent across the two experiments. In both experiments chicken activity, as measured by the proportion of birds standing up of those present in a 2.25-m2 floor grid in each pen, decreased with age (P less than .01) and was influenced by a light intensity by age interaction (P less than .05). It was concluded that bright lighting (greater than or equal to 10 1x) was not effective in reducing the incidence of leg disorders or in altering the SDS mortality rate.