Jennifer Lopez has reportedly hired extra security after animal rights extremists threatened to "slaughter" her.The fur-wearing singer-and-actress - who is regularly criticised by People for the Ethical Treatment of Animals (PETA) - has now reportedly been sent menacing letters.The letters are said to threaten "to kill her in public, just like the slaughtered animals whose fur she wears." Lopez's husband musician Marc Anthony is said to be so concerned for her safety, he has hired additional security for her. A source told the New York Daily News newspaper: "Marc Anthony has hired two off-duty police officers, in addition to her...