When the mother of a kitten has died or has abandoned him, the kitten may need hand raising. Kittens should only be taken from their mother after 6 weeks of age if possible. Young kittens need their mommy's milk for antibodies and nutrition so it is best that the mother feed her kittens as long as possible. Passive immunity normally lasts until about the kittens are 6-14 weeks. Orphans are most vulnerable to diseases since they do not have that protection.