Environment and Management Posters

The influences of cage design features, including feeder design and space, cage depth, cage area, stocking density, and the placement of resources, on production parameters of White Leghorns have not been fully assessed under commercial conditions. Assessing all these variables in a traditional experimental study would be difficult. An epidemiological approach, using variability in cage design among producers, is a useful tool to assess the impact of a multitude of variables on hen productivity. The objective of the current study was to identify aspects of cage design that affect feed efficiency and egg weight. A universal cage measurement system and an industry survey were developed. Out of 179 houses visited, a total of 167 yielded data suitable for analysis. Feed efficiency and egg weight outcomes were assessed from placement to 60 wk of age. Using GLM, a statistical model was identified that best described the variance in feed efficiency and egg weight. The analysis explicitly controlled for the effects of all other variables to avoid confounding effects. Among producers, the model explained 56% and 67% of the variation in feed efficiency and egg weight, respectively. Feed efficiency was not affected by cage or feeder design. Variation in feed efficiency among producers was small. Feed efficiency improved as caloric content of the feed increased up to 196 kcal/hen per d after which feed efficiency decreased with increasing caloric content. Egg weight was greater in A-frame houses where manure was removed regularly instead of being left in the house; with increasing cage floor slope; in cages where drinkers were placed either toward the front or the back of the cage rather than the middle; with more space per hen; and with feed with higher caloric intake. Perhaps because of its strong negative correlation with egg production, egg weight increased with less feeder space allocation and with shorter cage heights. These results show that cage design did not affect feed efficiency, but egg weight was influenced by several factors.