Eggs are essential nutritious food in our daily life, and they are also the main source of high-quality protein for kidney patients. At present, there are more types of eggs on the market, the price also varies greatly, different types of eggs in the nutritional composition of the difference has been a nutritional experts concerned about the problem. People are accustomed to the eggs are divided into eggs and eggs, the former are those free-range in the rural areas of Xieng Khouang field, every day in the woodland activities to forage for food, by eating live food and weeds and other natural food under the growth of chicken eggs, small. With the earth eggs very different growth environment, the so-called foreign eggs are large chicken farms through centralized management, centralized ingredients fed hen output, production is larger, larger head. Since foreign eggs are the mainstay of the current market, we now refer to them as ordinary eggs. Whether there is a difference in nutrients between the earth eggs and ordinary eggs has been the focus of concern for the majority of foodies, although folklore says that the earth eggs are more nutritious than ordinary eggs, and there is a big difference in price between them is an indisputable fact. But from the nutrition experts test results show that the nutrient content of the earth eggs and ordinary eggs is almost no big difference, ordinary chickens due to scientific feed formula, nutrient supplementation is balanced, so the ordinary chicken eggs are generally larger, containing nutrients (protein, trace elements, etc.) is not worse than the earth eggs. On the contrary, because of the unbalanced nutrition, the eggs laid by free-range chickens are smaller in size, and due to the poor growing environment, the eggs are easily contaminated. However, there are free-range state of earth chicken eat more green leafy vegetables, the yolk of the egg is high in carotenoids and vitamin B2, so the yolk of the egg is bigger and a little darker (attached table). It should be pointed out that different breeds of chickens and different growth environments, as well as the body mass of hens, age and many other factors, the quality of different kinds of eggs and individual eggs will have a big difference, this difference does not represent the quality of eggs, and different consumers will have different preferences for the size of the egg. So there is no conclusion as to who is better or worse than an ordinary egg, and eggs laid by chickens grown in different environments may differ in taste, which is entirely up to the individual to judge. Comprehensive expert opinion, the following methods can help identify the earth eggs and high-quality eggs: 1, color: earth eggs yolk color is not red, but cauliflower yellow and light orange. 2, the yolk is very tightly combined, the yolk is very thick, with a finger to poke or hand to hold will not be easy to break. 3.Egg white: thick. 4, eggshell: not particularly regular generally thicker, not large. 5, cooked state: yolks and egg whites are very clear between the contours of the yolk color uniformity, no obvious color stratification. Egg white is also uniform in color, the yolk is tightly combined, the appearance of the protein is smooth and tight. The taste is flavorful, with a strong egg aroma. The mouthfeel is delicate.