Madonna: Hires P.I. To Follow Rocco ... Deep Concerns About Guy Ritchie's Parenting Skills

Madonna is not relying on the paparazzi to document her son's life with Guy Ritchie in the middle of their custody war ... we're told she's hired a P.I. to get the lowdown in London first hand.

Multiple sources connected with the singer tell us, Madonna believes Guy has set no rules for 15-year-old Rocco and he's living dangerously ... not enrolled in school, hanging out in skate parks, smoking and essentially doing anything he wants.

We're told the animosity runs deep between Madonna and Guy ... she feels strongly their son needs structure and he's unable and unwilling to provide it.