To add to my previous post regarding skinning/processing roosters, even if you accidentally puncture the abdominal cavity (peritoneal cavity), that doesn't mess up the process as long as you don't puncture the guts with the knife (cross contamination). I quite often accidentally puncture the peritoneal cavity but since the bird is on its back, the abdomen is hollow and there is space between the peritoneal wall and the actual intestines/organs. So puncturing in itself doesn't mean you messed up as long as you don't puncture the guts with the knife you are using to harvest the meat. I hope all that makes sense.