[MyFairLacy]

I don't think size is unpredictable if you know your lines. I'm not talking about only parents and grandparents of the puppy - I'm talking about several generations. If a breeder knows the size of all the dogs in a puppy's pedigree for several generations and all the dogs are a similar size (say 4-6lbs for instance) then the puppy is 99% sure to stay between 4-6lbs. The reason size is often so unpredictable is because most breeders don't know their lines. They know the parents weight (ex. mom is 6lbs and dad is 4lbs) and possibly the grandparents (lets say 4lbs, 6lbs, 5lbs, and 3lbs). Okay so you'd think the puppy would most likely be between 4-6lbs but there could have been a great grandparents that was 7lbs and maybe a great great grandparent that was 9pounds...but the breeder didn't know about those bigger ones and since the parents are 4 and 6lbs says the puppy will be 5lbs full grown. Well the puppy ends up being 8lbs. Not unpredictable if the breeder had known their lines...they would have known that it was possible to end up with a bigger puppy. If you breed several generations of dogs with similar sizes, then size would not be unpredictable.