Is oz kg the mass of a dozen donuts?

No, "oz kg" is not a standard measurement of mass. Ounces (oz) and kilograms (kg) are two different units for measuring weight, with ounces being a smaller unit commonly used in the United States and kilograms being a metric unit. The mass of a dozen donuts would depend on the specific type and size of the donuts, but it would typically be measured in either ounces or kilograms, not a combination of both.