Welcome to YT! This is a great site with loads of information. When I joined 2 yrs ago I was clueless on the breed. This site has educated me on the breed.
I currently feed my babies Canidae lamb & rice formula. Its a little pricey but so worth it. This is the only food that has worked for my girl with allergies. When I first got my two they were also on Eukanuba and were little pooping machines...this was before I learned about all the by products in foods. Of course I learned this from this site too. Their food now contains no by products. My vet says it like this....any dog food that you can buy at a supermarket is not that great. I had a link with a list of good quality foods but I don't know where its at now. If I find it I'll send it to you.
It could have been the food that was making them gain weight quicky or it could be that they are going through a grow spurt. When I brought Mimi home she was almost 3 lbs at 12 weeks and now she is 11 lbs
More to love..but she really should be 8-9 lbs. She was on allergy meds which m ade her blow up a little so now we're working on trimming her up a little because of her having LP on her back knees. All the extra weight isn't good for her. Timmy on the other hand was almost 2 lbs at 12 weeks and now he's about 6 lbs. It really varies...some grow bigger than others.