The Chihuahua overpopulation in shelters are a problem in many cities in the Southwest. A few other rescues, such as a shelter in San Francisco which flew 68 Chihuahuas to New York with the help of actress Katherine Heigl, are also turning to cross-country solutions.
Action Alert (Animal Welfare): The laws for animal cruelty in the United States vary by state (ALDF has a helpful guide for the U.S. and Canada here; and international laws can be found using the Animal Legal & Historical Center's country search tool). To report a suspected case of animal abuse visit The Humane Society of the United States' tip page, or if the case seems urgent, call your local police department (or 911). There are several organizations doing great work to prevent animal abuse, to support them visit HSUS, ASPCA, and the Animal Legal Defense Fund.