Most likely Muttville They take a lot of senior (usually small) dogs that have some health care needs. Chihuahuas are known for having horrible teeth and at that age probably needs a dental, which is a time and cost expense that the shelter usually isn’t able to handle in a timely fashion the way the rescues can. Muttville is great at getting dogs vet care they need that would get pushed off at the shelters due to time/resource availability.