Translation:Byl jsem černá ovce rodiny.
Do we agree that "rodiny" here is on the genitive case ?
Why not Jsem byl...?
Jsem as a past tense auxiliary is a clitic and belongs to the second position https://forum.duolingo.com/comment/31466920 See also the Tips and notes.
I thought ‘the black sheep’ should be translated as ‘ bílý kůň‘
Bílý kůň means white horse.