Hi, It has been my opinion that if Mom is nursing them I would only supplement them.
They do have very small niples through Rivial. My 4lb yorkie just had 3 puppies 3 weeks ago and she has done a wonderful job. We just keep pumping her full of puppy food and puppy formula and supplementing the puppies with formula. We use one can of evaporated milk and one can of water and one egg yolk. No whites. Good luck you do evenually get some sleep. I have a wonderful husband that is retired and he sleeps nights and I sleep days.