I have a lot of females with red that extends in their heads. Some are the best type wise, so I can't cull for it entirely. How hard is this to be breed out and do you have any tips on compensation breeding/color of cock that would help eliminate this problem?
I've seen it, especially with large fowl, silver hens with varying degrees from not enough salmon to way too much extending into the muffs and head. My best advise is to continue to breed from the best you have available.
There are so called "modifying genes" that may dilute or enhance the salmon color and perhaps others that may extend it beyond the breast area. The modifying genes term is used very often to explain the differences in basic traits that we just can't label.
I don't get into double mating and feel it is really breeding two varieties to be shown under one variety name. If double mating is needed to produce exhibition birds then the Standards need to be changed to reflect reality.
Reeder's theories/ideas about the genes required to produce a "clean" white (silver) are not widely accepted. That isn't to say he is wrong, just that we all have opinions and experiences that we share. Much has changed about what is accepted about poultry genetics over the decades and there is a lot still unknown.
With bantam silver males the combs often look like they are half single comb and half pea comb (rr/Pp), but they are pure pea combs (rr/PP) with a modifying gene(s) that extends the center ridge. I've made a few outcrosses to try to bring in the proper genes, but haven't made much progress. Be careful not to breed to a variety that may have red shouldered males when outcrossing.