Natural ventilation has become a very viable alternative to fan ventilation for growing and finishing pigs. Like many newer technologies, it has had its problems and is following a typical learning curve. However, it is here to stay and will likely increase in popularity with rising energy costs and an increased use of straw bedded, group housing arrangements. Today’s naturally ventilated barn is quite a bit different than the early 80’s model. Sidewall and ridge openings are discussed along with controls for natural ventilation and building location.