I agree with changing her diet also. Not sure if I'd recommend Innova EVO as the protein is 42%. They have Innova Puppy which would be better.
Missy will be 4-1/2 months this coming Thursday and she just weighed
4 lb 8 ozs at the vet this morning.
It sounds like they are all pretty much in line with each other.
Missy just had a big growth spurt in length.