The Fix Your Critter Voucher program is a program for dogs and cats, with seven participating veterinary clinics in San Angelo, Wall, and Menard. Vouchers are sold once a month at PetSmart. The program began with 30 vouchers per month. Critter Shack is now able to offer 180 dog/cat vouchers each month. Since May of 2022, over 5,000 dogs and cats have been spayed/neutered/vaccinated through the Fix Your Critter Program. Critter Shack Rescue and Cassie's Place fund this program.

Critter Shack is a 501(c)3 nonprofit animal welfare organization whose mission is to advocate for humane treatment of animals, to provide an adoption program for rescue dogs and cats, to offer public education in animal welfare, and to offer a low cost spay/neuter program in the Concho Valley. The rescue program pays no salaries; all work is done by volunteers, ensuring that all funds donated benefit the rescue animals.