We had that happen to Clyde just about exactly a year ago now. I found a big half eaten rat in the drive way and a couple of days later, Clyde was sick. He started losin weight and wouldn't eat. Had problems going to the bathroom. We took him in and the doc X-Rayed him and all of his abdominal organs were all swapped around. It was weird. So the doc cut him open from his privates to his chest and went in and rearranged everything and got the blocked rat out. Sadly, we found out that Clyde has polycistic liver and kidney disease and he's probably not gonna live a normal length cat life.....BUT he's made a remarkable recovery and is doing great. We decided after that surgery to make him an inside only cat and I'm sure that's helped.