The Jersey Shore's Ronnie Ortiz Magro and his girlfriend Jen Harley got into a physical alteration in Las Vegas on Thursday. Us Weekly reports that the fight followed the death of their pitbull. A source said, ?Jen was supposed to be taking care of the dogs when he was away filming, and Ronnie came home to their house and found the dog dead in the pool.? Harley allegedly showed up ?unannounced? to the Las Vegas hotel where the cast of 'The Jersey Shore' is filming. An insider added, ?Ronnie and Jen have been fighting over their daughter. Ronnie has been filming the show in Vegas the last couple of days and Jen wouldn?t tell him where their daughter is." Ortiz-Magro and Harley welcomed a baby girl named Ariana Sky in April.