We hatch our Silkie eggs and we sell the chicks we don't want as straight run with a minimum of 4 (statistically 2 will be pullets and they will stay together). There are times we sell hens or pullets but usually with a rooster. On a rare occasion we will sell two girls together but we almost never sell single birds unless it is a rooster or there are special circumstances.
Our goal for hatching chicks is to improve the quality of our flock and to get the colors we want. As we keep young birds that are higher quality we may decide to give up hens that we no longer want to breed so we are more likely to list hens than pullets. Typically we would do this type of flock reduction in the Fall and not in the Spring.
I have found that many people want pullets at the youngest age possible but it is hard to guarantee the sex of a young Silkie so we basically only sell females as chicks or layers. We are not cranking out birds to sell, we sell birds as a means of improving our own birds.
The best way to get pullets is to get chicks and rehome the roosters. If you want to hatch eggs that is basically the same thing but you don't know what color or quality you will get that way. We hatch our eggs so we get first pick from what hatches but then because we wanted more splash we have sold many very nice blue chicks that would have otherwise been keepers. Anything with a disqualification that is pet quality is half price but if you are breeding you will not want to invest in culls either.
If you are allowed to have rooster, getting a breeding pair is a good way to hatch an endless supply of chicks and then you know what is going into them. You can keep the girls, sell the boys, and then after a year or two you can change out your rooster. With chicken math one pair can easily start a flock.
I would be happy to talk to you about your goals and help you get started. I am a former teacher so I like to teach.
Everyone wants pullets and as colour sexing , feather sexing and even vent sexing don't apply to silkies by the time you are able to guarantee the sex of the birds you will undoubtedly have a good ratio of Roos to rehome . The statistics aren't always 50/50, I once had a hatch of 13 , 9 Roos and 4 pullets.