Some may find this paper on the diversity of chicken genes interesting and/ or useful (if highly challenging)
https://bmcgenomics.biomedcentral.com/articles/10.1186/s12864-019-5727-9
Most of the breeds I have incorporated into my flock do not appear amongst the 174 populations in 32 countries on 4 continents, including a dozen commercial lines, included in their comprehensive study of the DNA. But *related* breeds appear in at least 3 different clusters (European, Middle East and East African, African and South American of 11 clusters in total), so I am optimistic that by my approach (which I repeat for convenience)
I have already got a relatively high proportion of polymorphic loci and relatively high heterozygosity - better than is observed among the typical European pure bred heritage breeds.
The paper has also alerted me to the genetic potential of Orpingtons - which I did not anticipate - as well as recognized oriental-origin breeds like Langshans, Cochins and Brahmas - to add some genetic diversity from cluster 11 (Asian, Chinese).
There is another cluster (Finnish), which may be the closest to the Swedish Flowers.
@Shadrach I believe you have a Finnish friend with a chicken habit; has he perchance indicated anything to you about their connection to or independence from other Scandinavian breeds? The supporting text for the paper just describes their history in terms very similar to those used for Swedish Flowers.