"Earth egg" refers to the eggs laid by free-range farmers, and "foreign egg" refers to the eggs laid by chickens raised with synthetic feed by chicken farms or professional chicken farmers.

The contents of fat and cholesterol in eggs are higher than those in foreign eggs, while the contents of calcium, iron, zinc, copper and manganese are similar to those in foreign eggs. The low fat and cholesterol content of "foreign eggs" produced in chicken farms may be related to the addition of a certain amount of dietary fiber in their feed.

From the appearance, ordinary eggs and native eggs are slightly smaller and have different sizes, while foreign eggs are similar in size and larger than native eggs. Touching the shell of the earth egg with your hand feels a little sticky, but the foreign egg is not obvious. The eggshells of foreign eggs are lighter in color, while local eggs are darker in color.