The Supporting Our Shelters Act amends the Animal Welfare Act to create a federal grant program through which the U.S. Department of Agriculture will award funding to animal shelters and rescue organizations to improve their ability to care for animals in their custody. These grants can be used to cover costs such as animal food, shelter facilities, veterinary services, recreational activities for animals, and staff hiring, training, and retention. Individual grants can last up to three years and may be renewed if the recipient organization submits required reports to the USDA. Grant recipients must provide detailed annual reports to the USDA documenting the types and numbers of animals they shelter, the outcomes for those animals, and how they spent the grant money. The USDA must also submit annual reports to Congress detailing how the program is working and how grantees are using funds to improve animal care.