The study evaluates how static pressure affects air velocity and flow through galvanized door inlets of different sizes. Testing was conducted on 44" X 7" and 44" X 14" inlets at static pressures of 0.05", 0.10", 0.15", and 0.20". It was found that air capacity increased with pressure, with a 41% increase when pressure rose from 0.05" to 0.10", but only a 22% increase from 0.10" to 0.15". This reflects Bernoulli's principle, which establishes a nonlinear relationship between static pressure and air velocity.Operating inlets above 0.15" offers minimal advantages and can reduce fan efficiency, leading to less fresh air intake. For optimal operation, it's recommended to base the number of inlets on their capacity at 0.10", resulting in specific requirements for poultry houses with high airflow needs.Inlet velocity should ideally be between 900 and 1,550 ft/min, adjusted according to temperature, with higher velocities needed in colder weather. Minimum ventilation suggests using a two-inch inlet opening, with increased capacities at larger openings. Taller inlets provide more airflow but require design features to reduce drafts. The study concludes that maintaining a static pressure around 0.10" optimizes fan efficiency and airflow distribution in poultry houses.