Yield is the economics of the shop. What a carcass cost against what the products cut from it sold for changes with every delivery, and an average across the month hides the deliveries that lost money.
The unpopular cuts are the real test. Loin sells itself; shin, brisket and belly were paid for at the same time and have to be turned into something people want, which is a decision made with numbers rather than instinct.
Prepared lines are a small factory inside the shop. Sausages, burgers and marinated products have recipes, batch sizes and a cost per kilo, and treating them as an afterthought is how a bestseller ends up losing money.
Christmas is scheduling, not selling. Several hundred orders, each with a weight and a collection window across three days, has to be planned against the counter staff actually available on those mornings.