Conveyor ovens for cooking food according to various embodiments include variable speed fans to deliver air from a plenum into at least two lower cooking zones below a conveyor of the oven, and at least one variable speed fan to deliver air from the plenum into one or more upper cooking zones above the conveyor, wherein a controller operates the fans delivering air into the lower cooking zones independently of each other and independently of the other fan. The fans can be controlled so that air delivered to a bottom side of the conveyor has a speed that is different in the different lower cooking zones and/or is different than air delivered to the top side of the conveyor. In some cases, the speed of the fans is predetermined and set in accordance with the type of food to be cooked.
