This is a very good idea and will help your puppy in more ways than I can count. Also, you can try adding a small amount of plain white cooked rice to her food and it will help her too. Good luck!
Probiotics are great for puppies! Also you can feed her some plain canned pumpkin. Her poop will still be mushy, if not mushier, and she will need to go out more, but it makes the whole process more comfy for her. And for some dogs canned pumpkin actually firms up the poop (and ironically if they are constipated it fixes that too).