Size of a blue nose pitbull?

Remember that Blue anything is just color. It is not a breed nor does it make a difference in behavior, strength, or any trait. It's just a color.

For size of any American Pit Bull Terrier (APBT) you would have to look at the parents. Good breeders will have both mother and father available for you to meet and pet to judge their characteristics so you know what to expect in their pups. The breeders should also answer all questions you have AND ask you questions. Size is a good question to bring up with them. If the parents of both parents are on site take a look at them too. If not, ask the breeder(s) how big those dogs were. Were either of the parents larger or smaller than the rest of the puppies in their litters? Knowing this will give you a general idea of what to expect with the puppy you get.

Bloodlines differentiate also. Some breeders breed for American Kennel Club standards, some for size, some for looks, some for build and weight. Many APBTs nowadays are bred to be shorter, wider, and more stocky than the standard thinner, sleeker, and slightly taller original. This type is bred for appearance first and foremost. If you want your dog to live a long and healthy life, take great care when deciding which bloodline to choose. Don't be careless just because a "blue nose" puppy is available out of someone's backyard. Great breeders don't allow their pups to go to new homes without having the necessary shots first and make sure they are 100% healthy and weaned.