I don't have specifics, but this is the information, minus the numbers, as basely and accurately as I am able to present.
PETA targets children: They send out graphic comic books to school children proclaiming “YOUR MOMMY KILLS ANIMALS” and to take your pets away from your parents until they stop cooking with meat, wearing wool, fishing, and etc.
Mercy killings: While PETA makes a whole lot of noise about animal rights, they don’t put this into practice all too well. In their work with the ABC--Animal Birth Control campaign, they spent too much time hawking their ideals, and ended up putting many shelter animals to sleep while only about 16 were adopted. (I think this is your direct answer.)
Sex and Charity: PETA prides itself on its half-naked protesters and nude advertisements, and even calls their vegan meal plans “veggie Viagra,” but really, how is this helping? Well, it gets attention, and that is one thing PETA does well, but all of this well-intentioned porn drives the meaning away from the message-- animals need love, and no matter how much you like skin flicks, there is no connection between human arousal and animal liberation.
Terror Within: Shadowy though they may be, there are some connections linking PETA to darker deeds, planted explosions, arson, and slandered the names of companies that are only slightly worse that the status quo. They have also trivialized devastating historical events such as the Holocaust and the African Slave Trade by comparing the human suffering to conditions on factory farms.
Looking back I don't really think I answered your question, but instead put up an anti-PETA argument. Sorry. I am such a troll.