Quote: Actually that isn't true. The birds without the vaulted skulls can have crests equal or greater than the ones with vaulted skulls. Once they grow up it is hard to tell which ones have it and which ones don't, without feeling their heads. It will make the shorter crests appear larger, but if you have the larger crests then vaults are not necessary.
The vaulted skulls were introduced to the Silkies when they were crossed with the Polish, probably in the 1800s. It was not an original breed trait - it was added to make the crests larger, which it did. It didn't make them larger because of the vaulted skull, but because of another gene for large crests which is also carried by the Polish. Beards were also added, they are also not an original Silkie trait.
I prefer the ones without the vaulted skulls because the breed didn't have it, so its not bulit for it - and the skulls are thinner, they get holes in them and they do have problems...