Doing the "old classic  lit" thang for another thread and came across this from the latter half of Felch's book below. It's "quaint" reading this book because it is from 1877 and   about the "art" of breeding. Lots of interesting terms to  translate into modern terms. But the info is very interesting. One thing to note is the advice based on   alleles unknown to them at the time. For instance, balancing undercolor in Felch's Light Brahmas needed done on  that eb ( Brown) allele based breed. But doesn't work for today's eWh ( Wheaten) allele based Light Sussex.
Excerpt:
"In nine cases in
 ten, chicks hatch with a perfect organism ; now, is
 not any work legitimate that secures its perfect 
 development? Should a chick hatch web-footed, the
web should be cut back to its proper structure, thus
 liberating the toes to grow in their legitimate angles.
 While the comb in Light Brahmas chicks will hatch
 perfect, its peculiar shape makes it less likely to 
 develop properly than a single comb. In many cases
 bad combs can be prevented by proper treatment.
 The first thing that nature does in case of a wound
 is to repair it. Therefore, if the middle division
 is seen to be growing too rapidly, the serrations of
 this division should be pricked with a sharp instru-
 ment so as to make them bleed. This process will
 check the growth of this division and allow the side
 divisions to grow into proportion with it. If the
 middle and one side seem to be growing faster than
 the other side, the same process of treatment applied
 to both will allow the weaker division to grow into
 proportion with them. An old cock may give a chick
 a severe peck in one side of the comb so as to turn it
 to one side. A corresponding wound on the other
 side will maintain it in its proper position. By this
 means we succeed in making the comb grow into
 proper shape. Is it not better to do so than to let it
 grow into an irregular, deformed mass, and then. turn
 butcher and cut and slash the comb, making a bad
 job of it, and receive the just censure of our fellow-
 breeders ? Three fourths of all the bad combs are
 the result of external causes and unnatural feeding to
 produce very large birds.
 The leg-feathering can be wonderfully assisted in
 its growth, and many a crooked toe saved by pulling
 all foul feathers. The skin of the foot and leg is
 tough, and the feathers oftentimes grow along under
 it, from one fourth to one half an inch before pene-
 trating the skin, thus causing the toe to turn in.
 I have pulled these feathers four times before suc-
 ceeding in making them grow properly.
 The breeders and amateurs as a rule are too lazy
 to attend to all this minutiae (and the writer is as
 guilty as anyone he knows, yet a guide-board may
 tell the way, if it docs not go itself). " end quote
The amateur's manual; or, Specific mating of thoroughbred fowls.
by  Felch, Isaac Kimball
Published 1877
https://babel.hathitrust.org/cgi/pt?id=uma.ark:/13960/t8kd2hs53;view=1up;seq=1
 This is his 1st book. It is about the art of breeding. Mendel's discoveries were forgotten when he died around 1865. He was not "rediscovered" until 1902. During the interim, when this book was written, there were "hybridists" and other scientists working on breeding problems. But genetics as a particular named Science did not appear till after 1902. So when this book was written ( and still for many years after), breeders used the "art" of breeding to perfect their animals and birds. In other words, they bred by comparison and physical attributes. As a painter chooses the correct quality canvas and proper quality and color of paint to make his masterpiece,... so in this book we  will see the author  discussing phenotypes and hues as breeding hallmarks for success instead of genetic ratios and percentages of breeding inheritances. Both art and science work together. This book is fascinating to read, esp. since it was written by an author so highly esteemed in remembrance. I have already found the answers to some of my Sussex questions this morning in reading some of it. ( Just a note here, mating Light Brahmas which are based on the eb ( Brown) allele is completely different from mating eWh (Wheaten) breeds like the Light Sussex. The breeding methods do not cross over.)
Again, mating "Partridge" colored birds based on eb (where the hen is "penciled") is different from breeding Partridge birds based on e+  wildtype (where the hen is stippled.)  See Judge Card's book for laws for breeding for color.
. Laws governing the breeding of standard fowls. c.1
    by Card, Wetherell Henry.  Published 1912
This is a small 55 page book. A treasure of distilled knowledge.
http://babel.hathitrust.org/cgi/pt?id=chi.087299559;view=1up;seq=5
Note these are Laws, not opinions or theories.  Judge Card was known
for his ability to take a complicated genetics topic and make it simple.
(read online free) Love, love, love this pithy little tome!