I just have one silkied cochin at this point. Yes, I believe you've answered my question -- that a split for silkied will pass that split on in a small percentage, so within that generation (a regular feathered group off by themselves, some of which are split) there could possibly be silkied offspring from that group. Please correct me if I don't have it right. THANKS!
You are right. There are 2 ways to approach this.
One is deliberate, painfully slow but controlled - carefully test breeding to identify splits that do carry this specific gene. The advantage is you know which is which, who is who, and don't accidently cull genes that you wish to propagate - as well as not tossing a wildcard out into the entire gene pool. The disadvantage is you are going to have to separate into pairs or very small groups, wait for the hen to clear from each of her sons in succession, hatch a bunch of eggs and wait to see if the breeding is between two splits and produces silkieds. Daughters of the hen can then be test bred to brothers that were proven splits, eggs hatched and if silkied offspring pop up - the daughter is also a split. Over and over until you build a base of proven splits and silkied offspring.
The second, that as I understand you are asking about, is to introduce the gene into your flock, let them do their thing and just wait and hope for random mating's to produce more silkied to snatch out and work with somewhere down the line in time. That could work. Keep in mind tho that these are recessive genes and the more birds in the flock without it the better the chance it will simply evaporate, diluted out or culled out either by your hand or circumstances. Kind of throw a bunch of mud against the wall and hope some sticks approach!
Perhaps a modified approach blending the two would be your best bet. You'd need a second pen that only contained the silkied gene hen and her offspring. Since it's a female you'd want to rotate at least a couple unrelated roos to her for some diversity in her offspring and then pull those roos before they could mate any of her daughters. Keep she and her offspring together, let them interbreed and wait for silkieds to pop up. This route keeps your possible splits concentrated and does not leach the gene out into your general population uncontrolled. Cull any non-silkied roos so that any offspring produced will be at least splits from hens that may or may not be splits. .Do not take any offspring descended from the original hen into your non-silkied group.
Keep in mind, any route chosen you are going to be hatching a LOT of eggs for each silkied chick to appear! Statisticly, with 2 splits breeding, you'll have to hatch 8 eggs for 1 silkied chick. Any breedings where BOTH parents are not splits will produce NONE visibly silkied. Never mind the offspring that "may" be splits from only one of the parents being a split, it's a shrinking possibility at best. Once you have your silkied base you can deliberately outcross for known 100% splits and take your breeding program forward accordingly.