For now, buy what she's eating! This baby was sent home with you entirely too small and too young! You don't want to do anything that will make her stop eating. These pups are at risk for hypoglycemia, and at just 1.5 lbs, your little one would be in big trouble if her sugar were to suddenly drop. Make sure you have either Karo syrup or NutriCal on hand just in case.
Oh, btw, welcome to YT. Please stick around and learn as much as you can. You are going to be reading a LOT of posts about why it isn't a good idea for a puppy to go to a new home before at least 12 weeks and a weight of 2 pounds. Please don't feel like anyone is blaming you. It's your breeder who should have known better! Everyone here is very passionate about these fur babies and wants what is best for them.
__________________ All we have to decide is what to do with the time that is given to us. - JRR Tolkien |