The Effects of Bird Density, Dietary Energy, Light Intensity, and Cage Level on the Reproductive Performance of Heavy Type Chickens in Wire Cages

Two experiments were conducted concurrently to study the effects of bird density, light intensity, cage level and dietary energy on egg production, body weight, feed consumption, feed efficiency, egg weight and mortality of heavy type chickens in wire cages. The study was conducted in a commercial, windowless, cage house equipped with modified stair-step cages 30.5 × 45.7 cm. in size. In Experiment 1, 960 pullets, housed at 1, 2, 3 and 4 birds per cage (1393, 697, 465 and 368 square centimeters per bird) were subjected to two light intensity treatments (1.5 to 3.0 foot candles and 0.5 to 1.2 foot candles), two diets (3060 and 2840 kcal. metabolizable energy), and two cage levels. Experiment 2 investigated the effects of density and cage level on the performance of 200 pullets housed two and three birds per cage and fed a commercially available caged layer diet. Data were collected from 20 to 52 weeks of age in Experiment 1, and, with the exception of feed consumption, from 20 to 72 weeks in Experiment 2. Greater bird density depressed egg production, increased mortality, and depressed body weight gain. However, under the conditions of this study, increasing density from two to three birds per cage failed to significantly depress production or increase mortality. Density effects on egg weight were not detected, nor were feed consumption and feed efficiency, investigated only at the two and three bird density levels. The higher energy diet treatment depressed egg production, increased body weight gain, and decreased total feed consumption. Dietary effects on egg weight, feed efficiency and mortality were not found to be significantly different. Effects due to differences in light intensity per se were negligible. The only significant effect was expressed by higher mortality under the high intensity treatment, probably related to the light intensity × diet interaction. Analysis revealed several statistically significant interactions, including a diet × light intensity effect which depressed egg production and increased mortality under the high energy diet × high light intensity treatment. The period × density, period × diet, and period × cage level interactions found for egg production, feed consumption, and body weight are discussed. Results suggest the desirability of further study to investigate the interaction of environmental and dietary factors. Feed consumption and body weight gain were found to be higher in the upper cage row groups. In Experiment 1, total hen-day production was higher in the upper cage row, but this effect was not observed in Experiment 2, at two and three bird densities.