Was the furball in Thelmer's "bedroom"? It could be that she's nesting. Female bunnies will pull their fur out in order to make a nest for their babies.

Miz Sophie scared the daylights out of me one day... I came home to find BUNCHES of fur in the corner of her cage and a cranky(!!) bunny sitting on top of it (she wouldn't let me touch her). I was so scared something was wrong... that she was hurt or that she was going to be bald ...

Sophie wasn't anywhere near a male (and Thelmer probably wasn't either) so I don't know what possesses them to do it. I don't know if it'd be considered a false pregnancy? Maybe they are/were just preparing for a weather change!

But yes, bunnies shed enormously!! And the hair is so fine that it flies everywhere. I've found that with Piper, using a squirt bottle of water works better than any comb/brush. I either squirt him or my hands and then give him a good body massage. It works out TONS of fur!