Why is my puppy licking its belly so much? Is it normal or a problem?

Puppies can lick at their bellies for a number of reasons, including normal behavior and occasional itches, allergies (unlikely in such a young puppy), fleas, ringworm, mange, among others. If Daisy's skin does not appear irritated and she is only licking rarely, this is likely not a cause for concern. Otherwise, make sure she is receiving a high quality flea/tick preventative regularly, such as Nexgard, Bravecto or Advantix. If the licking continues, she should be examined by her vet because excess licking can cause the development of skin infections.