And the vent is the opening under the tail out of which everything comes. Egg, poo, urates (chickens don't urinate exactly). They only have one multi-purpose opening. Very efficient! 😉
Those pelvic bones are not that close to the vent. You should be able to feel the width without getting your hand dirty. Hold the chicken across your body. Put the palm of your hand under the chicken's belly and reach upward toward the tail. The bones are a good inch or two south of the vent.