A disposable rodent cage used in both static and/or ventilated cage and rack systems, wherein the disposable cage includes a cage bottom. The cage may further be provided with a grommet disposed on the cage bottom and a bonnet constructed and arrange to fit over the cage bottom. The bonnet may further include a feeding and watering assembly. The cage may further include a filter cover that may be placed over an opening in the bonnet to cover the feeding and watering assembly. The bonnet may also include one or more elevated ribs disposed thereon to create an air seal when it is inserted into a canopy of a rack.