The SOP is the end all be all of heritage poultry. In many ways, it is the reason the breeds we have exist.
There are fours kinds of birds:
1) The most productive poultry in the world, that have ever existed, are the products of Western industry in Europe and North America.
2) Hatchery stock: Birds that are bred to color (broadly speaking) and comb with a kind of middle of the road egg production. When they are handled, be they "Sussex", "Dorkings, "Rocks", "Reds", "Wyandottes", or what have you, they all have the same, lean frame, and possess precious little of anything approaching true breed type.
3) There are the myriad backyard projects, all of which are touted by the owner as a worthy project, most of which have very little substantial backing whatsoever.
4) Then there are standard-bred, aka heritage fowl. The vast majority of them are held by breeders who breed to the standard with concern for type, feather, and symmetry. They are rare as all get out, and most large fowl breeds are holding on by a thread. Very few--exceedingly few--ever rise to the ranks of knowledge and passion manifested by these breeders, and I've met relatively few--none, really--breeders outside of these ranks who understand traditional poultry in a broadly experienced, meaningful way.
Production in non-industrial flocks has a rather impenetrable glass ceiling. Egg production without strict records and trap-nesting is unquestionably limited. Feed conversion rates in any modern sense of the word is impossible for the backyard breeder to work on. It requires sophisticated technology, and few if any non-industrial breeders have the finances or time necessary to follow this route.
Weight, however, is a breed characteristic, and that can be chases with a fair level of success in the back yard.
The first requirements for which I breed are weight, type, feather quality and symmetry. They are the foundation of any breed. There are basic phenotypical indicators for egg-production, of referred to loosely as the Hogan method, that can be followed, and the birds that score well in this fashion will maintain an appropriate level of production egg-wise and possess much of the abdomen quality that is necessary for a dual-purpose breed.
Remember that "production" is not a fixed trait; it is a level that is attained and must be maintained with every single generation. It is very quick to spiral to the center. A flock is only as productive as this year's breeding, and every flock is a closed book. There is no such things, in real time, as a productive breed. There are only productive strains, and most folk level out a strain in the first five years of working with it because it takes that much time to learn the strain, and by the time they do, it has changed. Then they begin again.
The best hope any strain of standard-bred poultry has is to be the object of a breeder's specialization and developed for appropriate levels of healthy productivity with the frameworks of the SOP. "Heritage" large fowl are threatened on all fronts, the thought that the folks who have brought them forward to this point and have kept them from disappearing all together were wrong is misguided. If one is going to engage heritage poultry on a meaningful level, one needs to acquire stock from a breeder who has underscored with insistence weight, type, feather quality and symmetry, and then, as one begins to understand poultry breeding, which will take a long time, one will learn how to select for the best and, hopefully, most productive birds as one goes.
It is,at any rate, no small feat.
