Roast pork sellers are one of the busiest during Chinese New Year. They start the day early roasting pork a day before Chinese New Year eve, cleaning the pigs, marinating and roasting them for few hours.
After that, cool down after roasting before delivering to the market. In old towns of Malaysia, they still used a DIY hooks to hook the roast pork delivering them to the market. The seller in the market is a different person, usually one of the family. He/she is very skilled in slicing with precision and weigh to sell. Here is a video of artisan pork seller.