Conveyor ovens for cooking food product according to various embodiments include a tunnel having an entrance and an exit, a conveyor to move the food product through the tunnel, and a canopy at the entrance and/or at the exit of the tunnel. The canopy can include a top spaced above the conveyor, and a skirt extending downwardly toward the conveyor, wherein the top, skirt, and conveyor define a partially enclosed space through which food product carried by the conveyor passes. Some conveyors ovens have a first configuration in which a cooking chamber of the oven has a first length, and a second configuration in which the cooking chamber is extended to have a longer second length, wherein food product on the conveyor is cooked along the entire first length in the first configuration, and is cooked along the entire second length in the second configuration.
