Carefoot did a lot of test matings, but I don't know if anyone really verified his work. It is tedious, takes multiple generations of birds, raising a lot, and keeping careful records. Hopefully accurate information will be supplied via DNA testing at some point. Then too, in some cases there is probably more than one way to reach a desired result. Look at blacks for example. They could be based on E or they could be based on ER or maybe on something else with adequate melanizers. There is a recessive black which admittedly I don't know much about as I have not run across it. Then there are the modifying genes. Why are some blacks produced with a green sheen, some dull, and some purple? Also, I know that my Brown Red large fowl are genetically different than my bantam Brown Reds, as some of the latter have the penquin look as chicks. John was here the weekend of June 4th and noticed it then. Until we have access to inexpensive DNA testing I think we will just have to use intuition, experience and the unverified opinion of others.