Like was said in the above post, lots of YBs are imported as unproven YBs. Amirs line are proven to produce Ivories. Now there are other bloodlines that come from Africa, but most are picked and nobody knows if they will prove out to actually be YBs untill they are bred. Ben Siegle and Amir worked together with the Orange Bellys, and produced the new looking Ivories last year. This line is compatible with a proven YB.