Well they had all of Europe and Northern Africa, so I'm sure it wasn't hard for them to find some.

Not really. Slavs were seen by Nazis as an inferior Asian race, and they thought Slavs were the leading exporter of Jews. In fact, one would argue that they hated Slavs as much, if not more, than Jews. Might explain why there were 20 million dead Slavs compared to 6 million dead Jews. Still disgustingly awful, but…