The reasons why the puppy is listless:

1. The dog may be sick, uncomfortable and listless.

2. It may be that the weather changes rapidly, and the dog cannot adapt to the weather changes in a short period of time, causing the dog to become listless.

3. Feeding the same kind of dog food for a long time or feeding expired food may cause gastrointestinal discomfort in puppies.

4. Possibly due to environmental and climate reasons, dogs will be in poor spirits when the temperature is relatively high.

5. There may be a new friend in the family, and the unfamiliarity with each other may cause the dog's mood to change.

6. The dog may be in estrus.

7. Being scolded by the owner. Bad Mood.

8. Infection with parasites, bacteria, viruses, etc. can cause anorexia and lack of energy in dogs.

9. Dogs may not eat after surgery or after giving birth, which is generally normal.

What characteristics do dogs have that indicate they are healthy:

1. Full of energy. Dogs are playful animals. If your dog is listless and unwilling to go out to play, your dog may be unwell.

2. Dental health. Dog teeth are an important part of a dog, especially older dogs. Healthy dogs have no odor in their mouths and their teeth are sharp and strong.

3. The stool is normal. Whether a dog is healthy can be observed from the dog's poop. A healthy dog's poop is yellow or brown, has a certain degree of coagulation and has no odor.

4. Eat normally. The dog's diet is consistent with normal growth conditions.