Alright, a lot of information to digest here.
Let's start by going over a few few different things we are going to be talking about here, simplified some, because that's how my brain operates best.
1) Vuture hocks is a resessive trait. Full blown VH requires a copy inherited from each parent. A full blown VH bird will pass on a copy to each and every one of it's young. A bird with only one copy will appear normal, but will still pass a copy to 50% of it's young.
2) All chickens are either gold or silver based. Only males can be split gold/silver. Females can not, they are one, or the other. Now there are a ton of enhanser/modifiers that can muddy the water here, but we're keeping it simple. Female chick's base color is determined by the their father. Male chicks color is a combination of both parents contributions.
3) There are two types of white. Recessive, which requires two copies to show itself, and acts kind of like a switch and turns off the color, resulting in an all white bird. And dominant white, which will show itself with only one copy present. Dominant white is more effective removing the color black from the feather, leaving the base color. To my understanding , buff laced is basically gold laced with the addition of dominant white. So these birds being called buff laced/gold laced split are buff laced carrying a single copy of dominant white, and have a 50-50 shot of passing dominant white on to their young.
Now to some of the particulars. In your first breeding pen consisting of the buff laced male, buff, gold, and a silver laced female. The silver laced female produced the silver/gold split laced cockerels. Her pullets would have been either gold or buff laced. None of the gold or buff laced hens produced any silver laced chicks with that buff laced male. Not sure what to make of white chicks out of this pen. It is possible it could be a silver/gold split cockerel out of the silver laced hen that recieved dominant white from dad, effectively removing the black lacing. Now one thing we have learned here by the presence of the VH silver/gold cockerels is that the silver laced hen carries a copy of VH, as does the buff laced male.
As to the second breeding, silver/gold split male over same hens. Did this breeding produce any full blown VH chicks ? Did you get any "white" pullets ? This breeding should have produced some clean silver laced pullets, unless mom threw dominant in the mix.
The breeding of the buff laced pair producing no VH chicks make me think the hen you used carried no VH. Which means half those chicks likely recieved a copy from Dad.
We know the old silver laced hen is carrying a single copy of VH. The pullet may be also, or may be clear. I would say you probably need to use both. You could also use the gold laced hens with a split silver/gold laced male to potentally produce both clean gold, or silver laced pullets, and cockerels, as well as more split cockerels.
If you know which buff laced female you pair mated to the buff male that produced the clean hocked chicks, I would get every chick out of her you can. She appears to be clear of VH.
