Something else to note is that there have been several severe "bottlenecks" in the genetic history of the breed. Bottleneck refers to times when the population drops to a low level.
In the 1980's, there were less than 500 birds worldwide, all of them concentrated in 3 rural areas in Sweden. Now, there are about 50 flocks in Sweden with about a thousand birds, perhaps more at this point, plus whatever is here in the US.
The US population started with FIFTEEN birds. That is a huge bottleneck. And that original import did NOT include any crested birds. The original flock's breeder had eliminated cresting from her birds, with no apparent detriment to her birds. These 15 birds actually only represented 3 bloodlines.
Some months later, 19 more joined the original 15, and this group included 4 crested birds. The crested birds originated from the Vomb region of Sweden.
IIRC, there was a third import, this one selected to lay larger eggs than the original imports.
We can want to breed for genetic diversity and in a landrace fashion all we want, but there is a limit to the genes, unless more birds are brought over from other farms, which would be limited by the original bottleneck. Who knows what characteristics did not come over from the mother land.
Landrace also indicates its evolution, but does not refer to how it was maintained. Apparently some Swedish breeders DID select for some characteristics.
