My beagle had a litter of 6 puppies a few ears ago and died the next day. I raised them all. They got many baths - per day. You just have to make sure you keep them warm afterward. Don't use dog shampoo. I bathed them with baby shampoo.
You can, but I would let the mother give them their bath. Week old pups can get cold very quickly and that can kill them. Also, you have to be careful of their skin. It is extremely delicate. It can dry out quickly. I wouldn't do it more than once a week. I agree with lulabelle, NEVER use dog or puppy shampoo on week old pups. The chemicals in them can hurt the puppies. You can use Dawn dishwashing liquid, though. That's what we did.