Newborn puppies should ideally gain weight daily during their first few weeks. After that, their growth rate can vary depending on their breed, size, and overall health. Puppies should generally double their birth weight within the first 7 to 10 days. Monitoring their weight gain is essential to ensure they grow and develop correctly. If a puppy does not gain or lose weight, it may be a sign of a health issue or inadequate nutrition, and you should consult your veterinarian for guidance.