Well....that depends, do you have the time and experience necessary to make the perfect chicken? Or are you trying to cook thousands of chickens, day after day, with people that don't have grandma's care or expertise.
Check out the video. Its an analogy we are trying to make comparing cooking chickens to producing thousands of identical parts at a world class manufacturing level, 100% quality, 100% on-time, at the lowest cost per part possible.
The more sites we visit, the more processes we audit, the more we see that variability is truly, in the words of Jack Welch, "the root of all evil". Process variability is what causes plants to have to build safety factors into their systems. And as these safety factors build over time, we see that they just continue to add to the cost per part and though they reduce the number of occurrences, they don't eliminate them, because the actual root cause to the problem is never identified or truly understood.
In this video, we reference a case study that documents how safety factors get built into processes as manufacturers try and keep problems from occurring , when they don't have the time, resources, systems or expertise to truly understand root cause. In this case an entire final wash process was added to the part flow in an effort to produce 100% quality. Even though the existing process was producing parts that met spec, "most of the time", non-spec parts occurred often enough that the plant had to do something to contain the problem.
Here's the issue though, not only does the extra wash process require added capital, operating costs, maintenance, increased processing time, process bottlenecks etc, it never addressed the actual root cause. So while it improved their quality yield, it still did not let them reach their 100% target.
If you are interested in reading more, follow this link to CI-222