For the most part, they are because they have a solid base. Placing the Aerobin on a platform of pavers or a wooden surface will prevent the rodents from chewing on the bottom edge of the base. However, if your composter is tucked in a corner, persistent rodents can chew through just about anything if left undisturbed for extended periods of time. Rodents don’t like to be out in the open or in an area that is heavily traveled with foot traffic.