You can pick them early, but it helps to rub the bedding all over your hands. I touch them to count them and check milk bands at day one or two, but I don't usually pick them up and physically hold them until probably after week one. When you clean, just clean around the nest, and I've done this as early as the same day as the birth without any effects. Just make sure before you do anything to the nest or babies or clean, take mom out and put her in a different box. It helps, for whatever reason. When they're older I've picked up the entire nest, babies and all, to clean. Good luck! They're adorable when they all start running around.