<http://tingilinde.typepad.com/starstuff/2014/02/a-list-of-collective-nouns.html>

Of course, business of ferrets comes from busyness of ferrets, just as
the work term business comes from busyness.

He combined collective nouns found in multiple sources, and business/
busyness is not alone for ferrets. There is an older term, too.

[Posted in FML 8052]