Lighting techniques for the domestic fowl

Synopsis

The investigation was designed to find lighting patterns for maximum performance from laying chickens. An experiment is described involving two strains of poultry and four rearing and two laying lighting treatments.

The rearing treatments were applied from day‐old to 18 weeks of age. Treatment 1 was considered to be the control and consisted of alternating periods of 6 hr light and 18 hr dark. Treatment 2 was 18 hr light and 6 hr dark from weeks 0–4 and then similar to treatment 1 from 4–18 weeks. Treatment 3 was similar to treatment 2 except that the light period was 9 instead of 6 hr from 4–18 weeks of age. Treatment 4 was similar to treatment 2 except that red instead of white light was used at the same intensity from 2–18 weeks of age.

Laying treatment A consisted of 6 hr light in each 24 hr at 18 weeks of age followed by 4 weekly increases of 45 min. light followed by weekly increases of 20 min. per week to the end of the experiment. Laying treatment B consisted of 9 hr light in each 24 hr at 18 weeks followed by weekly increases of 20 min. light per week to the end of the experiment. Birds reared on treatment 3 were not subjected to laying treatment A but all other rearing treatment groups were subjected to both laying treatments.

Within each laying treatment, rearing treatment 2 was found to be slightly later maturing, generally to have larger body and egg weights and to produce more eggs than treatment 1. Treatment 3B was earlier maturing, had larger body and egg weights and had lower egg production than treatment 2A. It is concluded that further investigation is required into the effects of constant daylengths, other than 6 hr between 4 and 18 weeks of age, on sexual maturity and production characters. Red, as opposed to white incandescent light during rearing, is found to have adverse effects on production characters.

The difference between laying treatments A and B is partly dependent on the associated rearing treatments. However, a large increase in daylength at point‐of‐lay, such as treatment B, hastens maturity and reduces egg production and egg weight compared to a more gradual increase such as treatment A.