A.C.
I just want to say that for those of you who think this is associated with the Humane Society of the United States, it's not. HSUS is a non-profit, most of whose money goes to the pockets of it's executives (only 1% of HSUS net profits are actually donated to actual shelters who are actually rescuing/saving pets).
Please realize that there are not enough shelters and funds to care for all the unwanted animals. The gas chamber, which sad and horrifying, it still probably a better and kinder end to their lives than a life of starvation and/or being hit by a car.