Studies on Optimum Rearing Density in Layer House

II. Optimum Width of Single Cage for White Leghorn Pullet of Light Weight

Abstract

Collaborative studies were carried out at 4 Prefectural Poultry Experiment Stations to find economically optimum cage size for egg-type layers of light body weight.
Six hundred 120-day-old White Leghorn hens of Strain A (average adult size 1.66kg) and 800 120-day-old White Leghorn hens of Strain B (average adult size 1.69kg) were reared in individual cages having width, of 21, 19.5, 18, 16.5 or 15cm, and the observation was done from 150 to 500 days of age.
Little difference in viability, egg production, quantity of egg production, feed intake and feed conversion (feed/egg) was observed among the hens of Strain A in the cages of difierent size, while a significant difference was observed between the hens of Strain B in the cages of 15cm wide and those in the other cages, the former being inferior to the latter.
Little difference in age at 50% lay and egg weight was observed among the hens of both strains reared in the cages of the different sizes.
Significantly different response between the hens of Strain A and B, having almost identical body weight and being reared in cages of 15cm wide, indicated the strain difference in the susceptibility to the stress of narrow cage, and the necessity to use different cages for different strain.