Maybe it's the food you are feeding them. Gravy Train??!! Alpo??!! They are probably pooping out more than their body is taking in nutritionally. That food is just lots of filler.
I feed EarthBorn Primitive Formula. No grains. My Cattle Dog puppy has grown 3 inches longer and 2 inches taller since I brought her home on July 24th just because she finally on some good food. She hasn't gained any weight since we got her. My vet has suggest increasing her feeding by 20-30% until she reaches a year old and has a chance to fully grow and fill out. Katie is super active and just burns up all the nutritional value of her food.
We cannot tolerate a world in which one in three women is a victim of domestic violence. Speak Out so it stops