[carmen in nj]

ok, sometimes that behavior is due to a lack of calcium in the mom's diet, that is why Calcium supplement is SO important during nursing for a mom, inexperience breeders don't know about that and take it as newborn rejection.
keep up with the puppy, at 4 weeks, he needs a mix of goat's milk, canned soft puppy food mixed in and by 6 weeks, you can add grinded puppy kibble to the mix, she should be eating this until about 10 weeks, when the slowly switch to dry puppy kibble can be done.
best of luck to you..