How long until you can touch your baby rat?

It depends on the mother rat. If she trusts you after giving birth, than you may be able to touch a baby rat the same day it's born. Being able to handle them as early as possible allows you to check to see if they're feeding and check their overall condition. Otherwise, you could wait a day or two before touching them, especially if the mother rat seems wary. It is also advised that you handle the baby rats as often as the mother rat will allow, so that it'll be easier for the babies to bond with and trust humans.