What Is The Growth Rate Of A Red Merle Puppy?

by Aussie Lover
(Salt Lake City, Utah)

I have a red merle puppy, she is about 3.5 months old. But she hasn't grown much at all. She is about an inch bigger than when we first got her, and we have taken her to the vet for her shots but she has not gained much weight either. We are feeding her all natural lamb puppy food, twice a day the recommended amount from our vet. We have a Miniature Aussie and he is about 3 years old, when he was a puppy he grew pretty quick. I am just worried she is not growing like she should, or maybe she is just smaller for she is the runt of the litter?