A rodent cage including a cage bottom having a plurality of integral side walls, a floor and an open top end. A peripheral lip extends continuously around the top end. A pair of recesses are disposed on the peripheral lip. A feeder assembly has a frame and at least one section descending therefrom. The frame has pair of flanges extending therefrom so that when the feeder assembly is disposed in the cage bottom the pair of flanges are mated with the pair of recesses, respectively. A bonnet is dimensioned in size for sealing the top end of the cage bottom. A lock is disposed on the bonnet for preventing rodents housed in the cage from displacing the bonnet from the cage bottom.