
Long Coat Chihuahua
Largest pup a whopping 7.5ozs!!! Which ended up under 6lbs as an adult, so still within the breed standard.
Smallest surviving 2.75ozs and she made just under 5lbs as an adult, so within standard.
This breed does not help you to "guesstimate" adult weight. I once had a family come to choose a bitch puppy, and the father didn't want a tiny adult. I recommended they look at the largest bitch, who was a good 100gms heavier than her 2 sisters. Dad was happy with that. All 3 pups owners kept in touch, and little miss big knickers is the smallest adult! :-)
I offered to have her back, and mum and both daughters said dad had been outvoted, as they loved her!