Animal rights campaigners in America have called on Kevin Federline to take custody of Britney Spears' dogs. People For The Ethical Treatment Of Animals (PETA) believe it's cruel to separate the couple's young sons, Sean Preston and Jayden James, from the mutts. Spears lost physical custody of her boys earlier this week (begs01Oct07) after reportedly ignoring a string of court-imposed demands and skipping mandatory drug tests. In an open letter to Federline, PETA President Ingrid E. Newkirk writes, "For the sake of your children and the animals who are at risk while in Ms. Spears' custody, we hope that you will do the right and best thing for all involved and pursue a custody order for the animals so that your sons can continue to have the company of the animals they've grown to adore."