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Here are some links to threads specifically pertaining to Silkies.
And here is the link to the breeders club.
Before deciding to breed Silkies, first you need to familiarize yourself with the breed and the breed standard. Find a mentor. Learn as much about them as possible. Silkies are readily available from most hatcheries and feed stores. They aren't hard to obtain, so you aren't likely to make much money. But good quality birds are harder to come by. Get yourself good stock. Work to breed your birds to meet the breed standard. You can sell your birds at any point. Some customers prefer to buy day olds. Others prefer to get their chicks once they no longer need supplemental heat. Some want started pullets that are close to laying age.
Regardless, you need a plan for those that don't sell, especially the young cockerels. And you need to be prepared to deal with chicks passing.
If your aim is to hatch a ton of chicks, and sell them all; and not breeding, keeping, and raising show quality birds; just don't. There are already a bunch of hatcheries turning out poor quality birds by the hundreds.
Bad quality silkies are a dime a dozen. If you seriously want to get into breeding you need to start with the best birds you can get. Look into local APA/ABA shows and get to know good breeders. Get a copy of the ABA SOP, or the APA SOP. There are many varieties of silkies out there so decide which one you want to concentrate on.
Junebuggena has listed some good links for you to check out. She also points out an important part of breeding - you need a plan to deal with excess birds (cockerels mostly). The fact is there will never be enough homes for every male hatched each year no matter how nice they are. You need a plan in place to deal with them.
When you sell them is personal preference. Some sell hatching eggs, chicks of various ages and/or started birds. For me, I will only sell cull pullets for layer flocks, and started birds for those interested in breeding. Excess males, and sometimes pullets, end up in the freezer. Everyone is different. You have to decide what your goal is.
You can not make Splash out of white and black. For Splash you need Blue. I think you meant 'paint'. But those genetics are pretty complicated, considering that Silkies are recessive white instead of dominant white.