Ludlow's painting from the first edition of Wright's Book of Poultry
(Note the coarseness of pencilling compared to the later plate)

Unfortunately, most pencilled Hamburghs seen today are crossed between cockerel and pullet strains and therefore, have many faults difficult to eradicate. The object of the serious breeder is to attempt to separate the two strains by judicious breeding and try to recreate strains of exhibition birds of both sexes. This is how I have gone about doing this in my own yard with good success.

First Year
Carefully look all your birds over and cull out any which have undesirable traits or deformities. The idea is to find birds which show strong traits of each strain.

The Females
Select females as close to exhibition quality as possible. They must have sound heads and be well marked across the breast. A common indicator of crossed strains is markings on the breast which appear as double or triple lacing rather than pencilling. Hens having these markings can be used in the first cross, but NEVER use any female which has a distinct break in the markings, showing feathers with no black at all. Look for good quality pencilling on the rump and thighs. The pencilling on the back and wings will most likely be a little mossy, this being acceptable. Select some with darker reddish bay ground colour and some with golden bay. Separate the females into pens which have birds of similar ground colour. Ideally, single mate. You may find you only have one of each colour female to use.... this is better than using birds which carry undesirable traits (I only used two females to create both my exhibition lines).

The Male
Select an UNRELATED male, which is primarily exhibition cockerel strain, but which still shows traits of a pullet strain. The most common indicators of pullet strain are a lack of clear, bright lacing in the tail furnishings, (such tails sometimes appearing a nutty brown colour rather than black) and more pencilling in the wing and rump than would usually be found on an exhibition cockerel. His ground colour may be a shade darker than that found in an exhibition male, but do not select a bird that is too dark. Avoid any birds which show white in the main wing feathers as this will increase in the offspring.
Use the one male bird exclusively in this first season.

The Offspring
The progeny of this first year will be a mixed lot. Cull heavily for physical defects and head faults. Any which come with white in the feather (commonly in the wing and on the hackle tips) are discarded. You will find that you will see two distinct colour variations in these first chickens as well as variations in markings. You will almost be able to tell which birds are from what mating, the differences are often that profound.
Cockerels
There will be two very distinct types of cockerels, easily distinguished by ground colour. The brighter coloured males will in all probability show improved tail markings and less black in the body. These will form the foundation of your cockerel strain.
The darker cockerels will have more black pencilling through the body and wings as well as poor tail markings, though you may find a slight improvement here if you used a nutty-brown tailed sire. Discard any which have dull brown patches in the plumage and lighter feather tips on the breast and underside. Select those which show more pencilling on the body and wings, though make sure the wing pencilling is as fine as possible and even. These cockerels will be used in your pullet strain.
Pullets
Any pullets with broken fronts must be discarded. Pullets which show clearer markings on the back and wings, with bright ground colour will form the foundation for your pullet strain. The ones with darker ground colour and coarser, mossy pencilling will be used in the cockerel strain. I have found often it is quite easy to pick the daughters of a particular hen from these first matings.

You have now built the foundations for both your strains. I must stress here, the need to cull heavily. Failure to do so now, will set you back in subsequent generations.

This essay is written from my own personal experiences and from hints given me by old breeders now passed on.