Hi Country
Well, from my own experience Ive never had a show line that did not have a recessive disqualifying trait that does not crop up once in a while. A basic understanding of genetics helps when breeding anything and it will give you excellent tools when it comes to understanding why things happen the way they do.
The missing piece of your puzzle is that you have no idea what the parents of the eggs you bought looked like or what their lineage was like. Some breeders may do a lot of what you suggest. Take the beautiful roo and even though he only has four toes use him as a breeder. Now, what if this same breeder has a hen that is beautiful except for her comb, its big and rough and oversized, but shes beautiful in every way other than that. Now the breeder is breeding a roo with a major fault, with a hen that has a major fault in the hopes that they will get a chick with neither. Unfortunately youll probably get the majority of chicks with DQs.
I find stabilizing a bloodline means line breeding and inbreeding. The way I was taught is to take the father and cross him back to the daughters, and take the mother and cross back to the sons. Then put the original parents back together. Now you have three potential lines to work with. Heres a drawing of the potential possibilities.
Once you have had a bloodline for a while you know to a certain degree what to expect. By introducing new blood into your own line you are adding unknown factors. So, on top of getting a few of the expected faults that you are used to, you now get new unexpected faults. Mind you this goes for strengths as well, not just faults.
If I was in your position I would continue to breed the bloodline you have been working with all along and keep it relatively pure. Then when you get to the point where you are not seeing improvements anymore go out and find one specific bird from another bloodline that has the strengths you want to add to your line. For instance if you have been breeding for three years and everything looks good, but you just dont get chicks with the heavy foot feathering that you want, go find a bird from an established breeder that has exceptional foot feathering, and then breed that bird into your line and cull cull cull. Hopefully you will be able to maintain all of the positive factors of your original line, plus the added foot feathering.
Clear as mud?
Oh, one other thing I was thinking about is also pay close attention to the way some breeders advertise their winnings. Here is an example: Champion Silkie Ok, to me this means absolutely nothing. There could have only been 3 Silkies in the class. Yup, they got Champion Silkie, big deal. Best of Breed Same thing with this title, not that big a deal really unless there were 25 Silkies in the class, or the competition is top of the line. Now, when you get to higher levels of winnings like, Champion Feather Leg, thats getting a bit better. This Silkie now probably competed against the Cochins, Brahmas, Booted Bantams etc. Once you get to things like Champion Bantam, Grand and Reserve of Show, etc youre probably looking at better birds, especially if the breeder has had these winning consistently and has been doing it for years.
Man, Ive really rambled on this one. Hope its not too much!
One last thing. Talk with lots of experienced breeders who have developed bloodlines, not people who bought champion birds to begin with.
Urban Coyote