Temperatures and performance in a tunnel-ventilated, high-rise layer house

Temperatures were recorded from winter to summer in a high-rise, bidirectio nally tunnel-ventilated commercial layer house. In cool weather, the house was ventilated through side wall baffle inlets and a series of ceiling inle ts. The temperature sensors were located in the vicinity of the tunnel inle ts (CENTER sites), near the ends of the house where the exhaust fans were l ocated (END sites), and midway between these locations (INTERMEDIATE sites) . Hens and eggs were weighed, and eggs sampled for specific gravity determi nations, once a month at the sites of the temperature sensors. In winter, t he CENTER sites were coolest and the INTERMEDIATE sites tended to be warmes t. In spring, there were no differences among areas in average daily temper ature. During summer, CENTER sensors were again coolest and END sensors wer e warmest. CENTER sites had the largest eggs during the winter and summer m onths. INTERMEDIATE sites tended to have the smallest eggs from January to March. Egg size variation among different areas might have been minimized i n winter by covering the tunnel curtain inlet, and in summer by using only information from the sensors nearest the fans to control fan operation when in tunnel ventilation mode. Hens in the lowest tier of cages consistently produced the largest eggs.