Although I see the logic behind it, I am very concerned about the food and water being withheld. At that young- not even four months yet right? And that teeny tiny I would really worry about potential dehydration or a hypo glycemic episode. Maybe when she gets a little older she will hold it through the night but right now I wouldn't worry about it mama
my lilah turned out to be quite a bit smaller than I anticipated. She is 4.5 lbs and holding at almost two- we visited with her sister a while back and she was twice her size! We have a potty pad and though I know some folks are more comfortable with outdoor training I just can't imagine having success with my tiny little gal and these sweeping Columbia gorge winds and endlessly dreary wet days. As far as the poop goes, I beleive royal canin puppy has more filler than some other dog foods. That said my dog is on the exact same food right now and I do a happy dance every day that she eats her kibble with joy because it has been so hard watching and waiting for her to eat every natural grain free raw dehydrated etc etcetera I kept trying to feed her until less than two months ago. I know some very intelligent and well respected members here feed it, her breeder fed it and her vet reccomends it- to top it off she actually eats it! So I'm sold- even though it has corn in it. And just choose to be grateful my dog doesn't have grain allergies. But she poops more (again I'm glad she eats more and I suppose that comes with it). Planning to switch her to adult food now that she is actually wiling I eat something and see how that goes. So all that said, perhaps an ex pen with a crate inside of it (left open of course) and a potty pad outside the crate might be a good solution for you guys right now. Most breeders don't allow their yorkie babies to leave home until they are twelve weeks and I know sometimes when they are super small like that they will hold on to them for even longer. So give it some time, she's still just a little baby
best of luck!