This has to be the number one question I get asked as a breeder. While there is no way to promise a size of a rottweiler from a puppy to full grown there is a way to get the “about size.”
No I am not trying to tap dance around and cover myself. In the dog world one of the oldest tricks is to take the weight of the sire and dam; then add them together, now divide by two.
Something like this (weight of sire + weight of Dam)/2 = the ABOUT size of your puppy at full growth. There is no sure fire way to know for sure; and there is always a give or take depending on the sex of the puppy.
In some cases Rottweilers don’t grow at the time they bred; so the ethical breeder will disclose this at the time of purchasing your puppy but the breeder should still able to give you the about weight based on the Grand Sires / Dams in the pedigree.
Sure it might be some work; but here again the ethical breeder should be willing to furnish this information about their bloodlines.
A lot of people, some breeders included, look at the size of the parents. They believe if they get their Rottweiler puppy from large parents their Rottweiler puppy will be large. This is not always the case as they fail to read the entire pedigree. Reading a Rottweiler pedigree is almost a lost art these days.
Another huge mistake is to over look the quality of the female Rottweiler (the bitch). So many, once again some breeders included, are so stuck on the male Rottweiler they over look the female Rottweiler. The breed a sub-par female to a large well known sire just to sell their puppies.
Just because they have Rottweiler Puppies for sale doesn’t mean they are ethical and know what they are talking about.