When puppies are born, many of their organs aren’t fully formed. This includes the brain, and puppies are very fragile. They spend the first few weeks of their lives developing rapidly.
Puppies are born with their eyelids shut, because their eyes aren’t developed. A newborn puppy’s eyes are extremely fragile. Never attempt to open a puppy’s eyes; they’re sensitive to life and can sustain damage for life.
Newborn puppies are also deaf, and relative silence is crucial for their developing ears. Forcing the puppy’s ears to respond to sound inputs before they’re fully developed could cause great damage.
It usually only takes a couple of weeks before the pup’s eyes open and they hear well. They still shouldn’t be removed from their mother until they’re at least eight weeks old. Some animals are born with the ability to leave thru mothers right away, but dogs are more like humans in this context; they need time with their mom in order to develop and be taught.