I dont think 3 pounds at 5 months is all that small. Diggy is almost 6 months now and is just over 3 pounds by a few ounces. I think he is very average or alittle below for this age. Yorkies are no different than humans, I think thats the reason for all these different answers. Human females are supposed to be done growwing at 14-16, I on the other hand grew until I was 18 and Im 5-9 now my sister is 5-1 and never grew past 5th grade ??? Same mom same dad and both of my parents are around 5-6. Ya just never know. Bella my 2 year old girl has not grown since 6 months old (she is 4.11) nor have her 2 sisters who are in my immediate family, all 3 girls just stopped right around 6-7 months. Now Diggy has really slowed in the growing he was gaining like a 3/4 a pound a month (he was less than a pound when I got him
) but since he hit 4 months he has really slowed down. Maybe he will hit a spurt here pretty quick but not looking good. I was hoping for a bigger boy but as long as he is healthy Im happy. My vet said he wont get much over 4 pounds, but who knows Very hard to predict!