2012 Annual Report 1a.Objectives (from AD-416): The objectives of this research are to evaluate energy usage patterns in modern broiler housing throughout the production cycle and to determine the effects of energy saving measures on thermal conditions and production efficiency in broiler chickens during the brooding phase. 1b.Approach (from AD-416): Effects of reduced energy usage regimens and measures to improve energy efficiency in modern broiler housing on the thermal environment and subsequent production efficiency will be evaluated. 3.Progress Report: Field data were collected in commercial broiler houses indicating that temperature distribution within the attic space is variable and dependent upon buoyancy driven convection. The field data were used to develop a computational flow simulation model to describe flow patterns and heat recovery from the attic space. The simulation showed inlet air flow paths are greatly affected by buoyancy driven flow and are distorted towards the shaded side of the roof. Distorted flow paths resulted in driving cooler air from the shaded section of roof towards the ceiling inlet, mixing with and reducing heat recovery. Design recommendations were formulated from parameterized simulation of construction elements to re-direct flow which resulted in projected heat gains up to 60%. The most critical elements to consider for improving heat gain for brooding is height of inlet point within the attic and physical re-direction of flow towards the shaded side of the attic to displace warm air towards the peak of the roof panels.