It is my understanding that a breed's Standard Of Perfection is the guide you use when breeding birds so they are as close to perfect as you can breed them.
I understand that there are other things to be considered when showing birds, including who the judge or judges are and how they think the breed should look. I have seen judges totally ignore the SOP for my species, this is not the way it should be, but it is a matter of fact that it happens. It shouldn't happen, but it does happen.
It should be that any individual breed association holds an associate membership in the APA and ABA, this allows them to provide that particular SOP for their membership. I think it is unfair of the APA and ABA to require any breeder to purchase the SOPs for breeds that they hold no interest in breeding. That is just my thought.
If you are a breeder of for example Dominique birds, then you should make your breeding selections to have the objective of creating a bird as close to the standard as possible.
Currently such a bird will most likely not be a show winner since the judges I've heard about think a Dominique should be more like a Barred Plymouth Rock than a true Dominique would be. This is an error by judging, not by breeding. It is also the reason I personally don't show birds. I am more interested in keeping my flock to the true Standard of 1915 than winning shows. It is my opinion that judges should be required to educate themselves on any breed's standard before they can judge that breed. I, as a breed shower, should not have to educate the judge(s) on my breed's Standard Of Perfection.
If you want to breed to the 1915 standard and then compared those birds to birds bred to the 1888 standard, which had inflated weights in an attempt to make the Dominique more closely resemble the Barred Rock except in comb. Then you would loose to the 1888 standard bred bird in today's show world. It would appear that changing the standard (the current SOP is 2010) for any reason should be a matter of great concern. However it, like most things, is more political in nature than keeping to pure breed characteristics that have been established for many years.
The copyright law changed in 1978 to last the life time of the author plus 70 years. Prior to that it lasted 95 years and would have then needed to be renewed.