Neonatal handling helps to stimulate a puppy or kitten’s neurological, endocrine and circulatory systems at a point when their brain’s are undergoing massive development. Studies have shown that exposing neonatal mammals to small, brief amounts of stress effectively inoculates them to future stress
Healthy puppies should meet other healthy, friendly animals that you know well and this can start around 3-4 weeks old. First introductions don't have to be face to face. Just seeing or smelling other animals from various distances is a great place to start and greatly reduces the chance for a negative interaction.
Raising a litter of puppies can be difficult and stressful. Add to that the enhanced stress of the last few years and many of us are at our breaking point. In 2020, I discovered the Wim Hof Method and it has changed my life for the better and made life for my puppies better too.