Recently, there has been much interest in and movement toward alternative housing systems for laying hens. Associated with the movement are many questions to be addressed concerning sustainability of such systems. This study quantifies electricity and propane usage in two side-by-side aviary hen houses each holding 50,000 laying hens, located in Iowa, USA. Electricity usage was also partitioned into different housing components, including ventilation, lighting, and manure-drying. Electricity for ventilation is most variable in that it was the largest of all the components with 60% of the total electric energy in summer but only approximately 5% in winter. The mechanical ventilation efficiency was approximately 25.5 m3/(hr-Watt) (15 CFM per Watt) at static pressure of 12.5 Pa (0.05 inch water column). The continuously running manure-drying blowers accounted for the largest proportion of electricity use in winter with approximately 350 kWh daily consumption. Over the 15-month monitoring period, both houses had an average electricity cost of 3.6 cents per kg of egg produced (based on the rate of $0.09/kWh). The fuel usage was minimal (less than 425 liters of propane in one year), although the winter weather during the monitoring period was milder than the historical climatic conditions
