Is it normal for puppies to be lethargic?

It is normal for puppies to be sleepy. Puppies can sleep for up to about 20 hours a day, which will ensure their growth and development. Because puppies need to reduce their calorie consumption and supply their body with nutrients to develop, sleeping is the best way to reduce calorie consumption. As long as the puppy has no other adverse symptoms, the owner should not worry too much. However, if the puppy is lethargic while showing loss of appetite, vomiting, diarrhea, etc., then the doctor needs to be consulted and treated promptly. Excessive sleepiness can be a sign of something wrong. The most common causes of excessive sleepiness in dogs include diabetes and hypothyroidism, but other diseases can also cause lethargy.