German Shepherd puppies how to see pure or impure

How can I tell if a German Shepherd puppy is pure or not? The period of purchase of the German Shepherd should be the most suitable 40 days after the birth of the puppy. The typical coat color of the German Shepherd is black back and yellow belly, some have white spots on the forehead, generally more black and brown, the head requires wedge-shaped, both wide and narrow and long, the maxillary incisors lightly cover the front 1/3 of the mandibular incisors, the gap between the maxillary and mandibular incisors is very small. The head should be wedge-shaped, with the top wide and narrow and long, and the upper jaw incisors lightly covering the front 1/3 of the lower jaw incisors, and the gap between the upper and lower jaw incisors is small. The most appropriate time to purchase a German Shepherd is 40 days after the birth of the puppy. Because the German Shepherd 40 days after birth, its size has developed to about the same size as an adult dog, there will no longer be major changes, so generally should be selected and pre-purchased 40 days after the birth of the dog, 40 days before the German Shepherd is difficult to identify whether purebred, the following are the characteristics of German Shepherd puppies, you can refer to the comparison. The selected dog should be physically healthy, lively and excited, naive and generous, with a strong appetite, no eye droppings, not thin, with moist and cool nose pads, a coat that is close to the body, lustrous and soft, and two eyes that are lively, vibrant, and move with ease. The typical coat color is black back and yellow belly, some have white spots on the forehead, generally more black and brown, wolf gray is also there, but rarely; around the muzzle to black is better. The color of the eyes is dark and dense, the eye shape is almond-shaped, the ears are upright and the tail is saber-dropped to meet the requirements; the height of the tail should not exceed the back level. The head requires a wedge shape, both wide and narrow and long. The muzzle of the male dog should be broad and should not be too slender. The incisors should be the front 1/3 of the maxillary incisors lightly covered by the mandibular incisors, like a scissor-like close contact, with a small gap between the maxillary incisors and mandibular incisors. The chest depth should reach the elbow, the knees are slightly curved, the abdomen is slightly closed, and the testicles of the male dog should be visible, not hidden testicles or single testicles. The limbs should be strong and the gait should be stable and comfortable. When selecting the dog should be allowed to walk, such as running a few steps, the hind limbs are combined together jumping, that may have injuries.