Physical and chemical properties of manure (e.g., moisture content, nitrogen content, and pH) can have significant impacts on ammonia (NH3) volatilization and thus air emissions. Different varieties of commercial laying hens have different production traits (e.g., feed consumption, water consumption, and egg production) and therefore have different manure characteristics. For instance, Hy-Line W-98 hens come into production at a younger age and lay larger eggs compared to Hy-Line W-36 hens. Similarly, brown variety hens have a larger body size and, therefore, a greater feed consumption compared to white variety hens. Studies also suggest that higher feed consumption can increase moisture content of the manure, which may increase nutrient loss (Smith et al., 2000) and ammonia emissions. Studies have further demonstrated that laying-hen genetics influences nutrient requirements (Krautmann, 1971; Christmas and Harms, 1978; North Carolina Cooperative Extension Service) and manure content due to different kidney structures (Wideman and Nissley, 1992).