NEW INTERMITTENT LIGHTING PROGRAM (THE READING SYSTEM) FOR LAYING PULLETS

1. Two intermittent lighting systems for laying hens are: the Biomitte nt system, using an asymmetric pattern of 0.25L:0.75D for 16 h followe d by 8D, which entrains oviposition to 24 h cycles and, compared with standard lighting programmes, gives the same egg number and egg size b ut a smaller feed cost, and a symmetrical system (4[3L:3D]) which allo ws intervals between ovipositions to stretch, giving bigger eggs with thicker shells, but yielding fewer eggs and achieving no saving in foo d intake. 2. A new system was devised to combine the increased egg siz e and shell thickness, characteristic of symmetrical intermittent ligh ting programmes, with the reduction in food intake which is a feature of programmes that reduce total activity time. The pattern tested was 24(0.25L:0.75D). 3. The results of 2 trials showed that this new syste m gives about 2% fewer eggs than conventional (Step Up) or Biomittent lighting with a 2% increase in mean egg size and a 3% improvement in s hell thickness at the end of the laying year. Feed consumption with th e new system was similar to that under Biomittent lighting and 6% lowe r than that recorded for Step Up lighting. 4. Mortality was lower with the new system than with Step Up lighting but not significantly so. F rom the evidence of other trials it is argued that intermittent lighti ng programmes which provide less than 8 h total illumination in 24 h g enerally reduce laying house mortality and may be regarded as benefici al to the welfare of the hen.